Bring in changes from joschi/openapi-diff

.circleci/config.yml

@@ -14,17 +14,23 @@ jobs:
       - restore_cache:
           key: openapi-diff-{{ checksum "pom.xml" }}
 
-      - run: mvn dependency:go-offline
+      - run: ./mvnw package -X
 
       - save_cache:
           paths:
             - ~/.m2
           key: openapi-diff-{{ checksum "pom.xml" }}
 
-      - run: mvn package -X
-
+      - run:
+          name: Save test results
+          command: |
+            mkdir -p ~/test-results/junit/
+            find . -type f -regex ".*/target/surefire-reports/.*xml" -exec cp {} ~/test-results/junit/ \;
+          when: always
       - store_test_results:
-          path: target/surefire-reports
+          path: ~/test-results
 
       - store_artifacts:
-          path: target/openapi-diff-*-SNAPSHOT.jar
+          path: core/target/openapi-diff-*-SNAPSHOT.jar
+      - store_artifacts:
+          path: cli/target/openapi-diff-*-SNAPSHOT.jar

.github/dependabot.yml

@@ -0,0 +1,8 @@
+version: 2
+updates:
+- package-ecosystem: maven
+  directory: "/"
+  schedule:
+    interval: daily
+    time: "04:00"
+  open-pull-requests-limit: 10

.github/workflows/maven.yml

@@ -0,0 +1,33 @@
+name: Test
+on:
+  push:
+    branches:
+    - master
+  pull_request:
+    branches:
+    - master
+jobs:
+  build:
+    runs-on: 'ubuntu-latest'
+    strategy:
+      fail-fast: false
+      matrix:
+        java_version: ['8', '11', '14']
+    env:
+      JAVA_OPTS: "-XX:+TieredCompilation -XX:TieredStopAtLevel=1"
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up JDK
+      uses: joschi/setup-jdk@v1
+      with:
+        java-version: ${{ matrix.java_version }}
+    - uses: actions/cache@v1
+      with:
+        path: ~/.m2/repository
+        key: ${{ runner.os }}-maven-${{ hashFiles('**/pom.xml') }}
+        restore-keys: |
+          ${{ runner.os }}-maven-
+    - name: Build with Maven
+      run: ./mvnw -V -B -ff install '-DskipTests=true' '-Dmaven.javadoc.skip=true'
+    - name: Run tests
+      run: ./mvnw -V -B -ff verify

.mvn/wrapper/maven-wrapper.properties

@@ -0,0 +1 @@
+distributionUrl=https://repo1.maven.org/maven2/org/apache/maven/apache-maven/3.6.3/apache-maven-3.6.3-bin.zip

Dockerfile

@@ -1,18 +1,10 @@
-FROM maven:3.5-jdk-8-alpine as build
-WORKDIR /app
-COPY ./ /app
-RUN mvn install -q && \
-  mvn package -q && \
-  ls /app/target/ && \
-  MVN_VERSION=$(mvn -q \
-    -Dexec.executable="echo" \
-    -Dexec.args='${project.version}' \
-    --non-recursive \
-    org.codehaus.mojo:exec-maven-plugin:1.6.0:exec) && \
-  mv /app/target/openapi-diff-${MVN_VERSION}-jar-with-dependencies.jar /app/openapi-diff.jar
+FROM openjdk:8-jdk-alpine AS build
+WORKDIR /build
+COPY ./ /build
+RUN ./mvnw -V -B -ff -P docker package -q
 
 FROM openjdk:8-jre-alpine
 WORKDIR /app
-COPY --from=0 /app/openapi-diff.jar /app
+COPY --from=build /build/cli/target/openapi-diff-jar-with-dependencies.jar /app/openapi-diff.jar
 ENTRYPOINT ["java", "-jar", "/app/openapi-diff.jar"]
 CMD ["--help"]

README.md

@@ -1,34 +1,63 @@
 # OpenAPI-diff 
 
-Compare two OpenAPI specifications(3.x) and render the difference to html file or markdown file.
+Compare two OpenAPI specifications (3.x) and render the difference to HTML plaintext, or Markdown files.
 
-[![CircleCI](https://circleci.com/gh/quen2404/openapi-diff/tree/master.svg?style=svg)](https://circleci.com/gh/quen2404/openapi-diff/tree/master)
+[![Test](https://github.com/joschi/openapi-diff/workflows/Test/badge.svg)](https://github.com/joschi/openapi-diff/actions?query=branch%3Amaster+workflow%3ATest+)
 
 # Requirements
-`jdk1.8+`
+
+* Java 8
 
 # Feature
-* Supports OpenAPi spec v3.0.
-* Depth comparison of parameters, responses, endpoint, http method(GET,POST,PUT,DELETE...)
+
+* Supports OpenAPI spec v3.0.
+* Depth comparison of parameters, responses, endpoint, http method (GET,POST,PUT,DELETE...)
 * Supports swagger api Authorization
 * Render difference of property with Expression Language
-* html & markdown render
+* HTML & Markdown render
 
 # Maven
 
-Available on [Maven Central](https://search.maven.org/#search%7Cgav%7C1%7Cg%3A%22com.qdesrame%22%20AND%20a%3A%22openapi-diff%22)
+Available on [Maven Central](https://search.maven.org/artifact/com.github.joschi.openapi-diff/core)
 
 ```xml
 <dependency>
-    <groupId>com.qdesrame</groupId>
-    <artifactId>openapi-diff</artifactId>
-    <version>1.2.0</version>
+  <groupId>com.github.joschi.openapi-diff</groupId>
+  <artifactId>core</artifactId>
+  <version>${openapi-diff-version}</version>
 </dependency>
 ```
 
 # Docker
 
-Available on [Docker Hub](https://hub.docker.com/r/quen2404/openapi-diff/) as `quen2404/openapi-diff`.
+Available on [Docker Hub](https://hub.docker.com/r/joschi/openapi-diff/) as `joschi/openapi-diff`.
+
+```bash
+# docker run joschi/openapi-diff:latest
+usage: openapi-diff <old> <new>
+    --debug                     Print debugging information
+    --error                     Print error information
+    --fail-on-changed           Fail if API changed but is backward
+                                compatible
+    --fail-on-incompatible      Fail only if API changes broke backward
+                                compatibility
+ -h,--help                      print this message
+    --header <property=value>   use given header for authorisation
+    --html <file>               export diff as html in given file
+    --info                      Print additional information
+ -l,--log <level>               use given level for log (TRACE, DEBUG,
+                                INFO, WARN, ERROR, OFF). Default: ERROR
+    --markdown <file>           export diff as markdown in given file
+    --off                       No information printed
+    --query <property=value>    use query param for authorisation
+    --state                     Only output diff state: no_changes,
+                                incompatible, compatible
+    --text <file>               export diff as text in given file
+    --trace                     be extra verbose
+    --version                   print the version information and exit
+    --warn                      Print warning information
+```
+
 
 ## Build the image
 
@@ -42,19 +71,20 @@ You can replace the local image name `local-openapi-diff` by any name of your ch
 
 ## Run an instance
 
-In this example the `$(pwd)/src/test/resources` directory is mounted in the `/specs` directory of the container
+In this example the `$(pwd)/core/src/test/resources` directory is mounted in the `/specs` directory of the container
 in readonly mode (`ro`).
 
 ```bash
 docker run -t \
-  -v $(pwd)/src/test/resources:/specs:ro \
-  quen2404/openapi-diff /specs/path_1.yaml /specs/path_2.yaml
+  -v $(pwd)/core/src/test/resources:/specs:ro \
+  joschi/openapi-diff /specs/path_1.yaml /specs/path_2.yaml
 ```
 
-The remote name `quen2404/openapi-diff` can be replaced with `local-openapi-diff` or the name you gave to your local image.
+The remote name `joschi/openapi-diff` can be replaced with `local-openapi-diff` or the name you gave to your local image.
 
 # Usage
-OpenDiff can read swagger api spec from json file or http.
+
+openapi-diff can read OpenAPI specs from JSON files or HTTP URLs.
 
 ## Command Line
 
@@ -70,13 +100,12 @@ usage: openapi-diff <old> <new>
  -l,--log <level>               use given level for log (TRACE, DEBUG,
                                 INFO, WARN, ERROR, OFF). Default: ERROR
     --markdown <file>           export diff as markdown in given file
- -o,--output <format=file>      use given format (html, markdown) for
-                                output in file
     --off                       No information printed
     --query <property=value>    use query param for authorisation
     --state                     Only output diff state: no_changes,
                                 incompatible, compatible
     --fail-on-incompatible      Fail only if API changes broke backward compatibility
+    --fail-on-changed           Fail if API changed but is backward compatible
     --trace                     be extra verbose
     --version                   print the version information and exit
     --warn                      Print warning information
@@ -100,6 +129,7 @@ public class Main {
 ### Render difference
 ---
 #### HTML
+
 ```java
 String html = new HtmlRender("Changelog",
         "http://deepoove.com/swagger-diff/stylesheets/demo.css")
@@ -117,6 +147,7 @@ try {
 ```
 
 #### Markdown
+
 ```java
 String render = new MarkdownRender().render(diff);
 try {
@@ -131,11 +162,13 @@ try {
 ```
 
 ### Extensions
+
 This project uses Java Service Provider Inteface (SPI) so additional extensions can be added. 
 
-To build your own extension, you simply need to create a `src/main/resources/META-INF/services/com.qdesrame.openapi.diff.compare.ExtensionDiff` file with the full classname of your implementation.  Your class must also implement the `com.qdesrame.openapi.diff.compare.ExtensionDiff` interface.  Then, including your library with the `openapi-diff` module will cause it to be triggered automatically.
+To build your own extension, you simply need to create a `src/main/resources/META-INF/services/com.qdesrame.openapi.diff.core.compare.ExtensionDiff` file with the full classname of your implementation.  Your class must also implement the `com.qdesrame.openapi.diff.core.compare.ExtensionDiff` interface.  Then, including your library with the `openapi-diff` module will cause it to be triggered automatically.
+
+# Examples
 
-# Example
 ### CLI Output
 
 ```text
@@ -234,6 +267,7 @@ To build your own extension, you simply need to create a `src/main/resources/MET
 ```
 
 ### Markdown
+
 ```markdown
 ### What's New
 ---
@@ -308,10 +342,12 @@ To build your own extension, you simply need to create a `src/main/resources/MET
 ```
 
 # License
+
 openapi-diff is released under the Apache License 2.0.
 
 # Thanks
-* Adarsh Sharma / [adarshsharma](https://github.com/adarshsharma)
 
+* Adarsh Sharma / [adarshsharma](https://github.com/adarshsharma)
+* Quentin Desramé / [quen2404](https://github.com/quen2404)
 * [Sayi](https://github.com/Sayi) for his project [swagger-diff](https://github.com/Sayi/swagger-diff) 
   which was a source of inspiration for this tool

cli/pom.xml

@@ -0,0 +1,67 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <parent>
+        <groupId>com.github.joschi.openapi-diff</groupId>
+        <artifactId>parent</artifactId>
+        <version>2.0.0-SNAPSHOT</version>
+    </parent>
+
+    <artifactId>cli</artifactId>
+    <packaging>jar</packaging>
+
+    <name>openapi-diff-cli</name>
+    <description>CLI for openapi-diff</description>
+
+    <dependencies>
+        <dependency>
+            <groupId>com.github.joschi.openapi-diff</groupId>
+            <artifactId>core</artifactId>
+            <version>2.0.0-SNAPSHOT</version>
+        </dependency>
+        <dependency>
+            <groupId>commons-cli</groupId>
+            <artifactId>commons-cli</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-lang3</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.slf4j</groupId>
+            <artifactId>slf4j-api</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.slf4j</groupId>
+            <artifactId>slf4j-log4j12</artifactId>
+        </dependency>
+    </dependencies>
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-assembly-plugin</artifactId>
+                <configuration>
+                    <descriptorRefs>
+                        <descriptorRef>jar-with-dependencies</descriptorRef>
+                    </descriptorRefs>
+                    <archive>
+                        <manifest>
+                            <mainClass>com.qdesrame.openapi.diff.cli.Main</mainClass>
+                        </manifest>
+                    </archive>
+                    <finalName>openapi-diff</finalName>
+                </configuration>
+                <executions>
+                    <execution>
+                        <id>make-assembly</id>
+                        <phase>package</phase>
+                        <goals>
+                            <goal>single</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
+</project>

src/main/java/com/qdesrame/openapi/diff/Main.java → cli/src/main/java/com/qdesrame/openapi/diff/cli/Main.java

@@ -1,12 +1,19 @@
-package com.qdesrame.openapi.diff;
+package com.qdesrame.openapi.diff.cli;
 
-import com.qdesrame.openapi.diff.model.ChangedOpenApi;
-import com.qdesrame.openapi.diff.output.ConsoleRender;
-import com.qdesrame.openapi.diff.output.HtmlRender;
-import com.qdesrame.openapi.diff.output.MarkdownRender;
+import com.qdesrame.openapi.diff.core.OpenApiCompare;
+import com.qdesrame.openapi.diff.core.model.ChangedOpenApi;
+import com.qdesrame.openapi.diff.core.output.ConsoleRender;
+import com.qdesrame.openapi.diff.core.output.HtmlRender;
+import com.qdesrame.openapi.diff.core.output.MarkdownRender;
 import java.io.File;
 import java.io.IOException;
-import org.apache.commons.cli.*;
+import org.apache.commons.cli.CommandLine;
+import org.apache.commons.cli.CommandLineParser;
+import org.apache.commons.cli.DefaultParser;
+import org.apache.commons.cli.HelpFormatter;
+import org.apache.commons.cli.Option;
+import org.apache.commons.cli.Options;
+import org.apache.commons.cli.ParseException;
 import org.apache.commons.io.FileUtils;
 import org.apache.commons.lang3.exception.ExceptionUtils;
 import org.apache.log4j.Level;
@@ -33,6 +40,11 @@ public static void main(String... args) {
             .longOpt("fail-on-incompatible")
             .desc("Fail only if API changes broke backward compatibility")
             .build());
+    options.addOption(
+        Option.builder()
+            .longOpt("fail-on-changed")
+            .desc("Fail if API changed but is backward compatible")
+            .build());
     options.addOption(Option.builder().longOpt("trace").desc("be extra verbose").build());
     options.addOption(
         Option.builder().longOpt("debug").desc("Print debugging information").build());
@@ -66,15 +78,6 @@ public static void main(String... args) {
             .argName("property=value")
             .desc("use query param for authorisation")
             .build());
-    options.addOption(
-        Option.builder("o")
-            .longOpt("output")
-            .hasArgs()
-            .numberOfArgs(2)
-            .valueSeparator()
-            .argName("format=file")
-            .desc("use given format (html, markdown) for output in file")
-            .build());
     options.addOption(
         Option.builder()
             .longOpt("markdown")
@@ -89,6 +92,13 @@ public static void main(String... args) {
             .argName("file")
             .desc("export diff as html in given file")
             .build());
+    options.addOption(
+        Option.builder()
+            .longOpt("text")
+            .hasArg()
+            .argName("file")
+            .desc("export diff as text in given file")
+            .build());
 
     final String message = "Hello logging!";
     // create the parser
@@ -148,45 +158,29 @@ public static void main(String... args) {
       if (!logLevel.equals("OFF")) {
         System.out.println(consoleRender.render(result));
       }
-      HtmlRender htmlRender = new HtmlRender();
-      MarkdownRender mdRender = new MarkdownRender();
-      String output = null;
-      String outputFile = null;
       if (line.hasOption("html")) {
-        output = htmlRender.render(result);
-        outputFile = line.getOptionValue("html");
+        HtmlRender htmlRender = new HtmlRender();
+        String output = htmlRender.render(result);
+        String outputFile = line.getOptionValue("html");
+        writeOutput(output, outputFile);
       }
       if (line.hasOption("markdown")) {
-        output = mdRender.render(result);
-        outputFile = line.getOptionValue("markdown");
+        MarkdownRender mdRender = new MarkdownRender();
+        String output = mdRender.render(result);
+        String outputFile = line.getOptionValue("markdown");
+        writeOutput(output, outputFile);
       }
-      if (line.hasOption("output")) {
-        String[] outputValues = line.getOptionValues("output");
-        if (outputValues[0].equalsIgnoreCase("markdown")) {
-          output = mdRender.render(result);
-        } else if (outputValues[0].equalsIgnoreCase("html")) {
-          output = htmlRender.render(result);
-        } else {
-          throw new ParseException("Invalid output format");
-        }
-        outputFile = outputValues[1];
-      }
-      if (output != null && outputFile != null) {
-        File file = new File(outputFile);
-        logger.debug("Output file: {}", file.getAbsolutePath());
-        try {
-          FileUtils.writeStringToFile(file, output);
-        } catch (IOException e) {
-          logger.error("Impossible to write output to file {}", outputFile, e);
-          System.exit(2);
-        }
+      if (line.hasOption("text")) {
+        String output = consoleRender.render(result);
+        String outputFile = line.getOptionValue("text");
+        writeOutput(output, outputFile);
       }
       if (line.hasOption("state")) {
         System.out.println(result.isChanged().getValue());
         System.exit(0);
       } else if (line.hasOption("fail-on-incompatible")) {
         System.exit(result.isCompatible() ? 0 : 1);
-      } else {
+      } else if (line.hasOption("fail-on-changed")) {
         System.exit(result.isUnchanged() ? 0 : 1);
       }
     } catch (ParseException e) {
@@ -204,6 +198,17 @@ public static void main(String... args) {
     }
   }
 
+  private static void writeOutput(String output, String outputFile) {
+    File file = new File(outputFile);
+    logger.debug("Output file: {}", file.getAbsolutePath());
+    try {
+      FileUtils.writeStringToFile(file, output);
+    } catch (IOException e) {
+      logger.error("Impossible to write output to file {}", outputFile, e);
+      System.exit(2);
+    }
+  }
+
   public static void printHelp(Options options) {
     HelpFormatter formatter = new HelpFormatter();
     formatter.printHelp("openapi-diff <old> <new>", options);

core/pom.xml

@@ -0,0 +1,66 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <parent>
+        <groupId>com.github.joschi.openapi-diff</groupId>
+        <artifactId>parent</artifactId>
+        <version>2.0.0-SNAPSHOT</version>
+    </parent>
+
+    <artifactId>core</artifactId>
+    <packaging>jar</packaging>
+
+    <name>openapi-diff-core</name>
+    <description>Library for comparing two OpenAPI specifications.</description>
+
+    <dependencies>
+        <dependency>
+            <groupId>io.swagger.parser.v3</groupId>
+            <artifactId>swagger-parser-v3</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>io.swagger.parser.v3</groupId>
+            <artifactId>swagger-parser</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>io.swagger.parser.v3</groupId>
+            <artifactId>swagger-parser-v2-converter</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>com.j2html</groupId>
+            <artifactId>j2html</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-collections4</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.slf4j</groupId>
+            <artifactId>slf4j-api</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>commons-httpclient</groupId>
+            <artifactId>commons-httpclient</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.projectlombok</groupId>
+            <artifactId>lombok</artifactId>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.slf4j</groupId>
+            <artifactId>slf4j-simple</artifactId>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+</project>

src/main/java/com/qdesrame/openapi/diff/OpenApiCompare.java → core/src/main/java/com/qdesrame/openapi/diff/core/OpenApiCompare.java

@@ -1,17 +1,17 @@
-package com.qdesrame.openapi.diff;
+package com.qdesrame.openapi.diff.core;
 
-import com.qdesrame.openapi.diff.compare.OpenApiDiff;
-import com.qdesrame.openapi.diff.model.ChangedOpenApi;
+import com.qdesrame.openapi.diff.core.compare.OpenApiDiff;
+import com.qdesrame.openapi.diff.core.model.ChangedOpenApi;
+import io.swagger.parser.OpenAPIParser;
 import io.swagger.v3.oas.models.OpenAPI;
-import io.swagger.v3.parser.OpenAPIV3Parser;
 import io.swagger.v3.parser.core.models.AuthorizationValue;
 import io.swagger.v3.parser.core.models.ParseOptions;
 import java.io.File;
 import java.util.List;
 
 public class OpenApiCompare {
 
-  private static OpenAPIV3Parser openApiParser = new OpenAPIV3Parser();
+  private static OpenAPIParser openApiParser = new OpenAPIParser();
   private static ParseOptions options = new ParseOptions();
 
   static {
@@ -113,6 +113,6 @@ private static OpenAPI readContent(String content, List<AuthorizationValue> auth
   }
 
   private static OpenAPI readLocation(String location, List<AuthorizationValue> auths) {
-    return openApiParser.read(location, auths, options);
+    return openApiParser.readLocation(location, auths, options).getOpenAPI();
   }
 }

src/main/java/com/qdesrame/openapi/diff/compare/ApiResponseDiff.java → core/src/main/java/com/qdesrame/openapi/diff/core/compare/ApiResponseDiff.java

@@ -1,10 +1,10 @@
-package com.qdesrame.openapi.diff.compare;
+package com.qdesrame.openapi.diff.core.compare;
 
-import static com.qdesrame.openapi.diff.utils.ChangedUtils.isChanged;
+import static com.qdesrame.openapi.diff.core.utils.ChangedUtils.isChanged;
 
-import com.qdesrame.openapi.diff.model.ChangedApiResponse;
-import com.qdesrame.openapi.diff.model.ChangedResponse;
-import com.qdesrame.openapi.diff.model.DiffContext;
+import com.qdesrame.openapi.diff.core.model.ChangedApiResponse;
+import com.qdesrame.openapi.diff.core.model.ChangedResponse;
+import com.qdesrame.openapi.diff.core.model.DiffContext;
 import io.swagger.v3.oas.models.responses.ApiResponse;
 import io.swagger.v3.oas.models.responses.ApiResponses;
 import java.util.LinkedHashMap;

core/src/main/java/com/qdesrame/openapi/diff/core/compare/CacheKey.java

@@ -0,0 +1,12 @@
+package com.qdesrame.openapi.diff.core.compare;
+
+import com.qdesrame.openapi.diff.core.model.DiffContext;
+import lombok.Value;
+
+@Value
+public class CacheKey {
+
+  String left;
+  String right;
+  DiffContext context;
+}

src/main/java/com/qdesrame/openapi/diff/compare/Comparable.java → core/src/main/java/com/qdesrame/openapi/diff/core/compare/Comparable.java

@@ -1,4 +1,4 @@
-package com.qdesrame.openapi.diff.compare;
+package com.qdesrame.openapi.diff.core.compare;
 
 public interface Comparable<T> {
 

src/main/java/com/qdesrame/openapi/diff/compare/ContentDiff.java → core/src/main/java/com/qdesrame/openapi/diff/core/compare/ContentDiff.java

@@ -1,11 +1,11 @@
-package com.qdesrame.openapi.diff.compare;
+package com.qdesrame.openapi.diff.core.compare;
 
-import static com.qdesrame.openapi.diff.utils.ChangedUtils.isChanged;
-import static com.qdesrame.openapi.diff.utils.ChangedUtils.isUnchanged;
+import static com.qdesrame.openapi.diff.core.utils.ChangedUtils.isChanged;
+import static com.qdesrame.openapi.diff.core.utils.ChangedUtils.isUnchanged;
 
-import com.qdesrame.openapi.diff.model.ChangedContent;
-import com.qdesrame.openapi.diff.model.ChangedMediaType;
-import com.qdesrame.openapi.diff.model.DiffContext;
+import com.qdesrame.openapi.diff.core.model.ChangedContent;
+import com.qdesrame.openapi.diff.core.model.ChangedMediaType;
+import com.qdesrame.openapi.diff.core.model.DiffContext;
 import io.swagger.v3.oas.models.media.Content;
 import io.swagger.v3.oas.models.media.MediaType;
 import java.util.*;

src/main/java/com/qdesrame/openapi/diff/compare/ExtensionDiff.java → core/src/main/java/com/qdesrame/openapi/diff/core/compare/ExtensionDiff.java

@@ -1,8 +1,8 @@
-package com.qdesrame.openapi.diff.compare;
+package com.qdesrame.openapi.diff.core.compare;
 
-import com.qdesrame.openapi.diff.model.Change;
-import com.qdesrame.openapi.diff.model.Changed;
-import com.qdesrame.openapi.diff.model.DiffContext;
+import com.qdesrame.openapi.diff.core.model.Change;
+import com.qdesrame.openapi.diff.core.model.Changed;
+import com.qdesrame.openapi.diff.core.model.DiffContext;
 
 public interface ExtensionDiff {
 

src/main/java/com/qdesrame/openapi/diff/compare/ExtensionsDiff.java → core/src/main/java/com/qdesrame/openapi/diff/core/compare/ExtensionsDiff.java

@@ -1,12 +1,12 @@
-package com.qdesrame.openapi.diff.compare;
+package com.qdesrame.openapi.diff.core.compare;
 
-import static com.qdesrame.openapi.diff.utils.ChangedUtils.isChanged;
-import static com.qdesrame.openapi.diff.utils.Copy.copyMap;
+import static com.qdesrame.openapi.diff.core.utils.ChangedUtils.isChanged;
+import static com.qdesrame.openapi.diff.core.utils.Copy.copyMap;
 
-import com.qdesrame.openapi.diff.model.Change;
-import com.qdesrame.openapi.diff.model.Changed;
-import com.qdesrame.openapi.diff.model.ChangedExtensions;
-import com.qdesrame.openapi.diff.model.DiffContext;
+import com.qdesrame.openapi.diff.core.model.Change;
+import com.qdesrame.openapi.diff.core.model.Changed;
+import com.qdesrame.openapi.diff.core.model.ChangedExtensions;
+import com.qdesrame.openapi.diff.core.model.DiffContext;
 import java.util.*;
 import java.util.function.Function;
 
@@ -29,9 +29,7 @@ public boolean isParentApplicable(
     if (extensions.size() == 0) {
       return true;
     }
-    return extensions
-        .entrySet()
-        .stream()
+    return extensions.entrySet().stream()
         .map(
             entry ->
                 executeExtension(

src/main/java/com/qdesrame/openapi/diff/compare/HeaderDiff.java → core/src/main/java/com/qdesrame/openapi/diff/core/compare/HeaderDiff.java

@@ -1,11 +1,11 @@
-package com.qdesrame.openapi.diff.compare;
+package com.qdesrame.openapi.diff.core.compare;
 
-import static com.qdesrame.openapi.diff.utils.ChangedUtils.isChanged;
+import static com.qdesrame.openapi.diff.core.utils.ChangedUtils.isChanged;
 
-import com.qdesrame.openapi.diff.model.ChangedHeader;
-import com.qdesrame.openapi.diff.model.DiffContext;
-import com.qdesrame.openapi.diff.utils.RefPointer;
-import com.qdesrame.openapi.diff.utils.RefType;
+import com.qdesrame.openapi.diff.core.model.ChangedHeader;
+import com.qdesrame.openapi.diff.core.model.DiffContext;
+import com.qdesrame.openapi.diff.core.utils.RefPointer;
+import com.qdesrame.openapi.diff.core.utils.RefType;
 import io.swagger.v3.oas.models.Components;
 import io.swagger.v3.oas.models.headers.Header;
 import java.util.HashSet;

src/main/java/com/qdesrame/openapi/diff/compare/HeadersDiff.java → core/src/main/java/com/qdesrame/openapi/diff/core/compare/HeadersDiff.java

@@ -1,10 +1,10 @@
-package com.qdesrame.openapi.diff.compare;
+package com.qdesrame.openapi.diff.core.compare;
 
-import static com.qdesrame.openapi.diff.utils.ChangedUtils.isChanged;
+import static com.qdesrame.openapi.diff.core.utils.ChangedUtils.isChanged;
 
-import com.qdesrame.openapi.diff.model.ChangedHeader;
-import com.qdesrame.openapi.diff.model.ChangedHeaders;
-import com.qdesrame.openapi.diff.model.DiffContext;
+import com.qdesrame.openapi.diff.core.model.ChangedHeader;
+import com.qdesrame.openapi.diff.core.model.ChangedHeaders;
+import com.qdesrame.openapi.diff.core.model.DiffContext;
 import io.swagger.v3.oas.models.headers.Header;
 import java.util.LinkedHashMap;
 import java.util.List;

src/main/java/com/qdesrame/openapi/diff/compare/ListDiff.java → core/src/main/java/com/qdesrame/openapi/diff/core/compare/ListDiff.java

@@ -1,9 +1,7 @@
-package com.qdesrame.openapi.diff.compare;
+package com.qdesrame.openapi.diff.core.compare;
 
-import com.qdesrame.openapi.diff.model.ChangedList;
-import lombok.Getter;
+import com.qdesrame.openapi.diff.core.model.ChangedList;
 
-@Getter
 public class ListDiff {
 
   public static <K extends ChangedList<X>, X> K diff(K instance) {

src/main/java/com/qdesrame/openapi/diff/compare/MapKeyDiff.java → core/src/main/java/com/qdesrame/openapi/diff/core/compare/MapKeyDiff.java

@@ -1,4 +1,4 @@
-package com.qdesrame.openapi.diff.compare;
+package com.qdesrame.openapi.diff.core.compare;
 
 import java.util.ArrayList;
 import java.util.LinkedHashMap;

src/main/java/com/qdesrame/openapi/diff/compare/MetadataDiff.java → core/src/main/java/com/qdesrame/openapi/diff/core/compare/MetadataDiff.java

@@ -1,9 +1,9 @@
-package com.qdesrame.openapi.diff.compare;
+package com.qdesrame.openapi.diff.core.compare;
 
-import static com.qdesrame.openapi.diff.utils.ChangedUtils.isChanged;
+import static com.qdesrame.openapi.diff.core.utils.ChangedUtils.isChanged;
 
-import com.qdesrame.openapi.diff.model.ChangedMetadata;
-import com.qdesrame.openapi.diff.model.DiffContext;
+import com.qdesrame.openapi.diff.core.model.ChangedMetadata;
+import com.qdesrame.openapi.diff.core.model.DiffContext;
 import io.swagger.v3.oas.models.Components;
 import java.util.Optional;
 

src/main/java/com/qdesrame/openapi/diff/compare/OAuthFlowDiff.java → core/src/main/java/com/qdesrame/openapi/diff/core/compare/OAuthFlowDiff.java

@@ -1,9 +1,9 @@
-package com.qdesrame.openapi.diff.compare;
+package com.qdesrame.openapi.diff.core.compare;
 
-import static com.qdesrame.openapi.diff.utils.ChangedUtils.isChanged;
+import static com.qdesrame.openapi.diff.core.utils.ChangedUtils.isChanged;
 import static java.util.Optional.ofNullable;
 
-import com.qdesrame.openapi.diff.model.ChangedOAuthFlow;
+import com.qdesrame.openapi.diff.core.model.ChangedOAuthFlow;
 import io.swagger.v3.oas.models.security.OAuthFlow;
 import java.util.Map;
 import java.util.Objects;

src/main/java/com/qdesrame/openapi/diff/compare/OAuthFlowsDiff.java → core/src/main/java/com/qdesrame/openapi/diff/core/compare/OAuthFlowsDiff.java

@@ -1,9 +1,9 @@
-package com.qdesrame.openapi.diff.compare;
+package com.qdesrame.openapi.diff.core.compare;
 
-import static com.qdesrame.openapi.diff.utils.ChangedUtils.isChanged;
+import static com.qdesrame.openapi.diff.core.utils.ChangedUtils.isChanged;
 import static java.util.Optional.ofNullable;
 
-import com.qdesrame.openapi.diff.model.ChangedOAuthFlows;
+import com.qdesrame.openapi.diff.core.model.ChangedOAuthFlows;
 import io.swagger.v3.oas.models.security.OAuthFlows;
 import java.util.Map;
 import java.util.Optional;

src/main/java/com/qdesrame/openapi/diff/compare/OpenApiDiff.java → core/src/main/java/com/qdesrame/openapi/diff/core/compare/OpenApiDiff.java

@@ -1,10 +1,14 @@
-package com.qdesrame.openapi.diff.compare;
+package com.qdesrame.openapi.diff.core.compare;
 
-import static com.qdesrame.openapi.diff.compare.PathsDiff.valOrEmpty;
+import static com.qdesrame.openapi.diff.core.compare.PathsDiff.valOrEmpty;
 
-import com.qdesrame.openapi.diff.model.*;
-import com.qdesrame.openapi.diff.model.ChangedExtensions;
-import com.qdesrame.openapi.diff.utils.EndpointUtils;
+import com.qdesrame.openapi.diff.core.model.ChangedExtensions;
+import com.qdesrame.openapi.diff.core.model.ChangedOpenApi;
+import com.qdesrame.openapi.diff.core.model.ChangedOperation;
+import com.qdesrame.openapi.diff.core.model.ChangedPath;
+import com.qdesrame.openapi.diff.core.model.ChangedPaths;
+import com.qdesrame.openapi.diff.core.model.Endpoint;
+import com.qdesrame.openapi.diff.core.utils.EndpointUtils;
 import io.swagger.v3.oas.models.OpenAPI;
 import io.swagger.v3.oas.models.PathItem;
 import io.swagger.v3.oas.models.security.SecurityRequirement;
@@ -22,7 +26,7 @@ public class OpenApiDiff {
 
   public static final String SWAGGER_VERSION_V2 = "2.0";
 
-  private static Logger logger = LoggerFactory.getLogger(OpenApiDiff.class);
+  private static final Logger logger = LoggerFactory.getLogger(OpenApiDiff.class);
 
   private PathsDiff pathsDiff;
   private PathDiff pathDiff;
@@ -44,8 +48,8 @@ public class OpenApiDiff {
   private ExtensionsDiff extensionsDiff;
   private MetadataDiff metadataDiff;
 
-  private OpenAPI oldSpecOpenApi;
-  private OpenAPI newSpecOpenApi;
+  private final OpenAPI oldSpecOpenApi;
+  private final OpenAPI newSpecOpenApi;
   private List<Endpoint> newEndpoints;
   private List<Endpoint> missingEndpoints;
   private List<ChangedOperation> changedOperations;
@@ -138,27 +142,19 @@ private void preProcess(OpenAPI openApi) {
             .values()
             .forEach(
                 pathItem ->
-                    pathItem
-                        .readOperationsMap()
-                        .values()
-                        .stream()
+                    pathItem.readOperationsMap().values().stream()
                         .filter(operation -> operation.getSecurity() != null)
                         .forEach(
                             operation ->
                                 operation.setSecurity(
-                                    operation
-                                        .getSecurity()
-                                        .stream()
+                                    operation.getSecurity().stream()
                                         .distinct()
                                         .collect(Collectors.toList()))));
         paths
             .values()
             .forEach(
                 pathItem ->
-                    pathItem
-                        .readOperationsMap()
-                        .values()
-                        .stream()
+                    pathItem.readOperationsMap().values().stream()
                         .filter(operation -> operation.getSecurity() == null)
                         .forEach(operation -> operation.setSecurity(distinctSecurityRequirements)));
       }

src/main/java/com/qdesrame/openapi/diff/compare/OperationDiff.java → core/src/main/java/com/qdesrame/openapi/diff/core/compare/OperationDiff.java

@@ -1,10 +1,10 @@
-package com.qdesrame.openapi.diff.compare;
+package com.qdesrame.openapi.diff.core.compare;
 
-import static com.qdesrame.openapi.diff.utils.ChangedUtils.isChanged;
+import static com.qdesrame.openapi.diff.core.utils.ChangedUtils.isChanged;
 
-import com.qdesrame.openapi.diff.model.ChangedOperation;
-import com.qdesrame.openapi.diff.model.ChangedParameters;
-import com.qdesrame.openapi.diff.model.DiffContext;
+import com.qdesrame.openapi.diff.core.model.ChangedOperation;
+import com.qdesrame.openapi.diff.core.model.ChangedParameters;
+import com.qdesrame.openapi.diff.core.model.DiffContext;
 import io.swagger.v3.oas.models.Operation;
 import io.swagger.v3.oas.models.parameters.Parameter;
 import java.util.List;
@@ -84,8 +84,7 @@ public void removePathParameters(Map<String, String> pathParameters, ChangedPara
   }
 
   public void removePathParameter(String name, List<Parameter> parameters) {
-    parameters
-        .stream()
+    parameters.stream()
         .filter(p -> "path".equals(p.getIn()) && name.equals(p.getName()))
         .findFirst()
         .ifPresent(parameters::remove);

src/main/java/com/qdesrame/openapi/diff/compare/ParameterDiff.java → core/src/main/java/com/qdesrame/openapi/diff/core/compare/ParameterDiff.java

@@ -1,11 +1,11 @@
-package com.qdesrame.openapi.diff.compare;
+package com.qdesrame.openapi.diff.core.compare;
 
-import static com.qdesrame.openapi.diff.utils.ChangedUtils.isChanged;
+import static com.qdesrame.openapi.diff.core.utils.ChangedUtils.isChanged;
 
-import com.qdesrame.openapi.diff.model.ChangedParameter;
-import com.qdesrame.openapi.diff.model.DiffContext;
-import com.qdesrame.openapi.diff.utils.RefPointer;
-import com.qdesrame.openapi.diff.utils.RefType;
+import com.qdesrame.openapi.diff.core.model.ChangedParameter;
+import com.qdesrame.openapi.diff.core.model.DiffContext;
+import com.qdesrame.openapi.diff.core.utils.RefPointer;
+import com.qdesrame.openapi.diff.core.utils.RefType;
 import io.swagger.v3.oas.models.Components;
 import io.swagger.v3.oas.models.parameters.Parameter;
 import java.util.HashSet;

src/main/java/com/qdesrame/openapi/diff/compare/ParametersDiff.java → core/src/main/java/com/qdesrame/openapi/diff/core/compare/ParametersDiff.java

@@ -1,11 +1,11 @@
-package com.qdesrame.openapi.diff.compare;
+package com.qdesrame.openapi.diff.core.compare;
 
-import static com.qdesrame.openapi.diff.utils.ChangedUtils.isChanged;
+import static com.qdesrame.openapi.diff.core.utils.ChangedUtils.isChanged;
 
-import com.qdesrame.openapi.diff.model.ChangedParameters;
-import com.qdesrame.openapi.diff.model.DiffContext;
-import com.qdesrame.openapi.diff.utils.RefPointer;
-import com.qdesrame.openapi.diff.utils.RefType;
+import com.qdesrame.openapi.diff.core.model.ChangedParameters;
+import com.qdesrame.openapi.diff.core.model.DiffContext;
+import com.qdesrame.openapi.diff.core.utils.RefPointer;
+import com.qdesrame.openapi.diff.core.utils.RefType;
 import io.swagger.v3.oas.models.Components;
 import io.swagger.v3.oas.models.parameters.Parameter;
 import java.util.ArrayList;
@@ -39,8 +39,7 @@ public ParametersDiff(OpenApiDiff openApiDiff) {
 
   public static Optional<Parameter> contains(
       Components components, List<Parameter> parameters, Parameter parameter) {
-    return parameters
-        .stream()
+    return parameters.stream()
         .filter(param -> same(refPointer.resolveRef(components, param, param.get$ref()), parameter))
         .findFirst();
   }

src/main/java/com/qdesrame/openapi/diff/compare/PathDiff.java → core/src/main/java/com/qdesrame/openapi/diff/core/compare/PathDiff.java

@@ -1,9 +1,9 @@
-package com.qdesrame.openapi.diff.compare;
+package com.qdesrame.openapi.diff.core.compare;
 
-import static com.qdesrame.openapi.diff.utils.ChangedUtils.isChanged;
+import static com.qdesrame.openapi.diff.core.utils.ChangedUtils.isChanged;
 
-import com.qdesrame.openapi.diff.model.ChangedPath;
-import com.qdesrame.openapi.diff.model.DiffContext;
+import com.qdesrame.openapi.diff.core.model.ChangedPath;
+import com.qdesrame.openapi.diff.core.model.DiffContext;
 import io.swagger.v3.oas.models.Operation;
 import io.swagger.v3.oas.models.PathItem;
 import java.util.List;

src/main/java/com/qdesrame/openapi/diff/compare/PathsDiff.java → core/src/main/java/com/qdesrame/openapi/diff/core/compare/PathsDiff.java

@@ -1,9 +1,9 @@
-package com.qdesrame.openapi.diff.compare;
+package com.qdesrame.openapi.diff.core.compare;
 
-import static com.qdesrame.openapi.diff.utils.ChangedUtils.isChanged;
+import static com.qdesrame.openapi.diff.core.utils.ChangedUtils.isChanged;
 
-import com.qdesrame.openapi.diff.model.ChangedPaths;
-import com.qdesrame.openapi.diff.model.DiffContext;
+import com.qdesrame.openapi.diff.core.model.ChangedPaths;
+import com.qdesrame.openapi.diff.core.model.DiffContext;
 import io.swagger.v3.oas.models.PathItem;
 import io.swagger.v3.oas.models.Paths;
 import java.util.*;
@@ -42,9 +42,7 @@ public Optional<ChangedPaths> diff(
               PathItem leftPath = left.get(url);
               String template = normalizePath(url);
               Optional<String> result =
-                  right
-                      .keySet()
-                      .stream()
+                  right.keySet().stream()
                       .filter(s -> normalizePath(s).equals(template))
                       .findFirst();
               if (result.isPresent()) {

src/main/java/com/qdesrame/openapi/diff/compare/ReferenceDiffCache.java → core/src/main/java/com/qdesrame/openapi/diff/core/compare/ReferenceDiffCache.java

@@ -1,6 +1,6 @@
-package com.qdesrame.openapi.diff.compare;
+package com.qdesrame.openapi.diff.core.compare;
 
-import com.qdesrame.openapi.diff.model.DiffContext;
+import com.qdesrame.openapi.diff.core.model.DiffContext;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Map;

src/main/java/com/qdesrame/openapi/diff/compare/RequestBodyDiff.java → core/src/main/java/com/qdesrame/openapi/diff/core/compare/RequestBodyDiff.java

@@ -1,12 +1,12 @@
-package com.qdesrame.openapi.diff.compare;
+package com.qdesrame.openapi.diff.core.compare;
 
-import static com.qdesrame.openapi.diff.utils.ChangedUtils.isChanged;
+import static com.qdesrame.openapi.diff.core.utils.ChangedUtils.isChanged;
 import static java.util.Optional.ofNullable;
 
-import com.qdesrame.openapi.diff.model.ChangedRequestBody;
-import com.qdesrame.openapi.diff.model.DiffContext;
-import com.qdesrame.openapi.diff.utils.RefPointer;
-import com.qdesrame.openapi.diff.utils.RefType;
+import com.qdesrame.openapi.diff.core.model.ChangedRequestBody;
+import com.qdesrame.openapi.diff.core.model.DiffContext;
+import com.qdesrame.openapi.diff.core.utils.RefPointer;
+import com.qdesrame.openapi.diff.core.utils.RefType;
 import io.swagger.v3.oas.models.media.Content;
 import io.swagger.v3.oas.models.parameters.RequestBody;
 import java.util.HashSet;

src/main/java/com/qdesrame/openapi/diff/compare/ResponseDiff.java → core/src/main/java/com/qdesrame/openapi/diff/core/compare/ResponseDiff.java

@@ -1,11 +1,11 @@
-package com.qdesrame.openapi.diff.compare;
+package com.qdesrame.openapi.diff.core.compare;
 
-import static com.qdesrame.openapi.diff.utils.ChangedUtils.isChanged;
+import static com.qdesrame.openapi.diff.core.utils.ChangedUtils.isChanged;
 
-import com.qdesrame.openapi.diff.model.ChangedResponse;
-import com.qdesrame.openapi.diff.model.DiffContext;
-import com.qdesrame.openapi.diff.utils.RefPointer;
-import com.qdesrame.openapi.diff.utils.RefType;
+import com.qdesrame.openapi.diff.core.model.ChangedResponse;
+import com.qdesrame.openapi.diff.core.model.DiffContext;
+import com.qdesrame.openapi.diff.core.utils.RefPointer;
+import com.qdesrame.openapi.diff.core.utils.RefType;
 import io.swagger.v3.oas.models.Components;
 import io.swagger.v3.oas.models.responses.ApiResponse;
 import java.util.HashSet;

src/main/java/com/qdesrame/openapi/diff/compare/SchemaDiff.java → core/src/main/java/com/qdesrame/openapi/diff/core/compare/SchemaDiff.java

@@ -1,14 +1,14 @@
-package com.qdesrame.openapi.diff.compare;
+package com.qdesrame.openapi.diff.core.compare;
 
 import static java.util.Optional.ofNullable;
 
-import com.qdesrame.openapi.diff.compare.schemadiffresult.ArraySchemaDiffResult;
-import com.qdesrame.openapi.diff.compare.schemadiffresult.ComposedSchemaDiffResult;
-import com.qdesrame.openapi.diff.compare.schemadiffresult.SchemaDiffResult;
-import com.qdesrame.openapi.diff.model.ChangedSchema;
-import com.qdesrame.openapi.diff.model.DiffContext;
-import com.qdesrame.openapi.diff.utils.RefPointer;
-import com.qdesrame.openapi.diff.utils.RefType;
+import com.qdesrame.openapi.diff.core.compare.schemadiffresult.ArraySchemaDiffResult;
+import com.qdesrame.openapi.diff.core.compare.schemadiffresult.ComposedSchemaDiffResult;
+import com.qdesrame.openapi.diff.core.compare.schemadiffresult.SchemaDiffResult;
+import com.qdesrame.openapi.diff.core.model.ChangedSchema;
+import com.qdesrame.openapi.diff.core.model.DiffContext;
+import com.qdesrame.openapi.diff.core.utils.RefPointer;
+import com.qdesrame.openapi.diff.core.utils.RefType;
 import io.swagger.v3.oas.models.Components;
 import io.swagger.v3.oas.models.ExternalDocumentation;
 import io.swagger.v3.oas.models.media.ArraySchema;

src/main/java/com/qdesrame/openapi/diff/compare/SecurityDiffInfo.java → core/src/main/java/com/qdesrame/openapi/diff/core/compare/SecurityDiffInfo.java

@@ -1,19 +1,17 @@
-package com.qdesrame.openapi.diff.compare;
+package com.qdesrame.openapi.diff.core.compare;
 
-import com.qdesrame.openapi.diff.model.ChangedList;
+import com.qdesrame.openapi.diff.core.model.ChangedList;
 import io.swagger.v3.oas.models.security.SecurityRequirement;
 import io.swagger.v3.oas.models.security.SecurityScheme;
 import java.util.List;
 import java.util.Optional;
 import lombok.AllArgsConstructor;
-import lombok.Getter;
-import lombok.Setter;
+import lombok.Data;
 
-/** Created by adarsh.sharma on 11/01/18. */
-@Getter
-@Setter
+@Data
 @AllArgsConstructor
 public class SecurityDiffInfo {
+
   private String ref;
   private SecurityScheme securityScheme;
   private List<String> scopes;
@@ -30,8 +28,7 @@ public static SecurityRequirement getSecurityRequirement(
 
   public static Optional<List<SecurityDiffInfo>> containsList(
       List<List<SecurityDiffInfo>> securityRequirements, List<SecurityDiffInfo> leftSecurities) {
-    return securityRequirements
-        .stream()
+    return securityRequirements.stream()
         .filter(rightSecurities -> sameList(leftSecurities, rightSecurities))
         .findFirst();
   }
@@ -44,14 +41,20 @@ public static boolean sameList(
 
   @Override
   public boolean equals(Object o) {
-    if (this == o) return true;
-    if (o == null || getClass() != o.getClass()) return false;
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
 
     SecurityDiffInfo that = (SecurityDiffInfo) o;
 
     if (securityScheme != null
         ? !securityScheme.equals(that.securityScheme)
-        : that.securityScheme != null) return false;
+        : that.securityScheme != null) {
+      return false;
+    }
     return scopes != null ? scopes.equals(that.scopes) : that.scopes == null;
   }
 

src/main/java/com/qdesrame/openapi/diff/compare/SecurityRequirementDiff.java → core/src/main/java/com/qdesrame/openapi/diff/core/compare/SecurityRequirementDiff.java

@@ -1,10 +1,10 @@
-package com.qdesrame.openapi.diff.compare;
+package com.qdesrame.openapi.diff.core.compare;
 
-import static com.qdesrame.openapi.diff.utils.ChangedUtils.isChanged;
+import static com.qdesrame.openapi.diff.core.utils.ChangedUtils.isChanged;
 
-import com.qdesrame.openapi.diff.model.ChangedSecurityRequirement;
-import com.qdesrame.openapi.diff.model.ChangedSecurityScheme;
-import com.qdesrame.openapi.diff.model.DiffContext;
+import com.qdesrame.openapi.diff.core.model.ChangedSecurityRequirement;
+import com.qdesrame.openapi.diff.core.model.ChangedSecurityScheme;
+import com.qdesrame.openapi.diff.core.model.DiffContext;
 import io.swagger.v3.oas.models.Components;
 import io.swagger.v3.oas.models.security.SecurityRequirement;
 import io.swagger.v3.oas.models.security.SecurityScheme;
@@ -30,9 +30,7 @@ public SecurityRequirementDiff(OpenApiDiff openApiDiff) {
 
   public static SecurityRequirement getCopy(LinkedHashMap<String, List<String>> right) {
     SecurityRequirement newSecurityRequirement = new SecurityRequirement();
-    right
-        .entrySet()
-        .stream()
+    right.entrySet().stream()
         .forEach(e -> newSecurityRequirement.put(e.getKey(), new ArrayList<>(e.getValue())));
     return newSecurityRequirement;
   }

src/main/java/com/qdesrame/openapi/diff/compare/SecurityRequirementsDiff.java → core/src/main/java/com/qdesrame/openapi/diff/core/compare/SecurityRequirementsDiff.java

@@ -1,12 +1,12 @@
-package com.qdesrame.openapi.diff.compare;
+package com.qdesrame.openapi.diff.core.compare;
 
-import static com.qdesrame.openapi.diff.utils.ChangedUtils.isChanged;
+import static com.qdesrame.openapi.diff.core.utils.ChangedUtils.isChanged;
 
-import com.qdesrame.openapi.diff.model.ChangedSecurityRequirement;
-import com.qdesrame.openapi.diff.model.ChangedSecurityRequirements;
-import com.qdesrame.openapi.diff.model.DiffContext;
-import com.qdesrame.openapi.diff.utils.RefPointer;
-import com.qdesrame.openapi.diff.utils.RefType;
+import com.qdesrame.openapi.diff.core.model.ChangedSecurityRequirement;
+import com.qdesrame.openapi.diff.core.model.ChangedSecurityRequirements;
+import com.qdesrame.openapi.diff.core.model.DiffContext;
+import com.qdesrame.openapi.diff.core.utils.RefPointer;
+import com.qdesrame.openapi.diff.core.utils.RefType;
 import io.swagger.v3.oas.models.Components;
 import io.swagger.v3.oas.models.security.SecurityRequirement;
 import io.swagger.v3.oas.models.security.SecurityScheme;
@@ -39,8 +39,7 @@ public SecurityRequirementsDiff(OpenApiDiff openApiDiff) {
 
   public Optional<SecurityRequirement> contains(
       List<SecurityRequirement> securityRequirements, SecurityRequirement left) {
-    return securityRequirements
-        .stream()
+    return securityRequirements.stream()
         .filter(rightSecurities -> same(left, rightSecurities))
         .findFirst();
   }
@@ -63,9 +62,7 @@ public boolean same(SecurityRequirement left, SecurityRequirement right) {
 
   private List<Pair<SecurityScheme.Type, SecurityScheme.In>> getListOfSecuritySchemes(
       Components components, SecurityRequirement securityRequirement) {
-    return securityRequirement
-        .keySet()
-        .stream()
+    return securityRequirement.keySet().stream()
         .map(
             x -> {
               SecurityScheme result = components.getSecuritySchemes().get(x);

src/main/java/com/qdesrame/openapi/diff/compare/SecuritySchemeDiff.java → core/src/main/java/com/qdesrame/openapi/diff/core/compare/SecuritySchemeDiff.java

@@ -1,10 +1,10 @@
-package com.qdesrame.openapi.diff.compare;
+package com.qdesrame.openapi.diff.core.compare;
 
-import static com.qdesrame.openapi.diff.utils.ChangedUtils.isChanged;
+import static com.qdesrame.openapi.diff.core.utils.ChangedUtils.isChanged;
 
-import com.qdesrame.openapi.diff.model.ChangedSecurityScheme;
-import com.qdesrame.openapi.diff.model.ChangedSecuritySchemeScopes;
-import com.qdesrame.openapi.diff.model.DiffContext;
+import com.qdesrame.openapi.diff.core.model.ChangedSecurityScheme;
+import com.qdesrame.openapi.diff.core.model.ChangedSecuritySchemeScopes;
+import com.qdesrame.openapi.diff.core.model.DiffContext;
 import io.swagger.v3.oas.models.Components;
 import io.swagger.v3.oas.models.security.SecurityScheme;
 import java.util.HashSet;

src/main/java/com/qdesrame/openapi/diff/compare/schemadiffresult/ArraySchemaDiffResult.java → core/src/main/java/com/qdesrame/openapi/diff/core/compare/schemadiffresult/ArraySchemaDiffResult.java

@@ -1,8 +1,8 @@
-package com.qdesrame.openapi.diff.compare.schemadiffresult;
+package com.qdesrame.openapi.diff.core.compare.schemadiffresult;
 
-import com.qdesrame.openapi.diff.compare.OpenApiDiff;
-import com.qdesrame.openapi.diff.model.ChangedSchema;
-import com.qdesrame.openapi.diff.model.DiffContext;
+import com.qdesrame.openapi.diff.core.compare.OpenApiDiff;
+import com.qdesrame.openapi.diff.core.model.ChangedSchema;
+import com.qdesrame.openapi.diff.core.model.DiffContext;
 import io.swagger.v3.oas.models.Components;
 import io.swagger.v3.oas.models.media.ArraySchema;
 import io.swagger.v3.oas.models.media.Schema;

src/main/java/com/qdesrame/openapi/diff/compare/schemadiffresult/ComposedSchemaDiffResult.java → core/src/main/java/com/qdesrame/openapi/diff/core/compare/schemadiffresult/ComposedSchemaDiffResult.java

@@ -1,12 +1,12 @@
-package com.qdesrame.openapi.diff.compare.schemadiffresult;
+package com.qdesrame.openapi.diff.core.compare.schemadiffresult;
 
-import com.qdesrame.openapi.diff.compare.MapKeyDiff;
-import com.qdesrame.openapi.diff.compare.OpenApiDiff;
-import com.qdesrame.openapi.diff.model.ChangedOneOfSchema;
-import com.qdesrame.openapi.diff.model.ChangedSchema;
-import com.qdesrame.openapi.diff.model.DiffContext;
-import com.qdesrame.openapi.diff.utils.RefPointer;
-import com.qdesrame.openapi.diff.utils.RefType;
+import com.qdesrame.openapi.diff.core.compare.MapKeyDiff;
+import com.qdesrame.openapi.diff.core.compare.OpenApiDiff;
+import com.qdesrame.openapi.diff.core.model.ChangedOneOfSchema;
+import com.qdesrame.openapi.diff.core.model.ChangedSchema;
+import com.qdesrame.openapi.diff.core.model.DiffContext;
+import com.qdesrame.openapi.diff.core.utils.RefPointer;
+import com.qdesrame.openapi.diff.core.utils.RefType;
 import io.swagger.v3.oas.models.Components;
 import io.swagger.v3.oas.models.media.ComposedSchema;
 import io.swagger.v3.oas.models.media.Discriminator;
@@ -42,15 +42,15 @@ public <T extends Schema<X>, X> Optional<ChangedSchema> diff(
 
         Discriminator leftDis = leftComposedSchema.getDiscriminator();
         Discriminator rightDis = rightComposedSchema.getDiscriminator();
-        if (leftDis == null
-            || rightDis == null
-            || leftDis.getPropertyName() == null
-            || rightDis.getPropertyName() == null) {
-          throw new IllegalArgumentException(
-              "discriminator or property not found for oneOf schema");
-        } else if (!leftDis.getPropertyName().equals(rightDis.getPropertyName())
-            || (CollectionUtils.isEmpty(leftComposedSchema.getOneOf())
-                || CollectionUtils.isEmpty(rightComposedSchema.getOneOf()))) {
+        if ((leftDis == null && rightDis != null)
+            || (leftDis != null && rightDis == null)
+            || (leftDis != null
+                && rightDis != null
+                && ((leftDis.getPropertyName() == null && rightDis.getPropertyName() != null)
+                    || (leftDis.getPropertyName() != null && rightDis.getPropertyName() == null)
+                    || (leftDis.getPropertyName() != null
+                        && rightDis.getPropertyName() != null
+                        && !leftDis.getPropertyName().equals(rightDis.getPropertyName()))))) {
           changedSchema.setOldSchema(left);
           changedSchema.setNewSchema(right);
           changedSchema.setDiscriminatorPropertyChanged(true);
@@ -109,15 +109,14 @@ private Map<String, String> getMapping(ComposedSchema composedSchema) {
       reverseMapping.put(ref, schemaName);
     }
 
-    if (composedSchema.getDiscriminator().getMapping() != null) {
+    if (composedSchema.getDiscriminator() != null
+        && composedSchema.getDiscriminator().getMapping() != null) {
       for (String ref : composedSchema.getDiscriminator().getMapping().keySet()) {
         reverseMapping.put(composedSchema.getDiscriminator().getMapping().get(ref), ref);
       }
     }
 
-    return reverseMapping
-        .entrySet()
-        .stream()
+    return reverseMapping.entrySet().stream()
         .collect(Collectors.toMap(Map.Entry::getValue, Map.Entry::getKey));
   }
 }

src/main/java/com/qdesrame/openapi/diff/compare/schemadiffresult/SchemaDiffResult.java → core/src/main/java/com/qdesrame/openapi/diff/core/compare/schemadiffresult/SchemaDiffResult.java

@@ -1,15 +1,15 @@
-package com.qdesrame.openapi.diff.compare.schemadiffresult;
+package com.qdesrame.openapi.diff.core.compare.schemadiffresult;
 
-import static com.qdesrame.openapi.diff.utils.ChangedUtils.isChanged;
+import static com.qdesrame.openapi.diff.core.utils.ChangedUtils.isChanged;
 import static java.util.Optional.ofNullable;
 
-import com.qdesrame.openapi.diff.compare.ListDiff;
-import com.qdesrame.openapi.diff.compare.MapKeyDiff;
-import com.qdesrame.openapi.diff.compare.OpenApiDiff;
-import com.qdesrame.openapi.diff.model.Change;
-import com.qdesrame.openapi.diff.model.ChangedSchema;
-import com.qdesrame.openapi.diff.model.DiffContext;
-import com.qdesrame.openapi.diff.model.schema.*;
+import com.qdesrame.openapi.diff.core.compare.ListDiff;
+import com.qdesrame.openapi.diff.core.compare.MapKeyDiff;
+import com.qdesrame.openapi.diff.core.compare.OpenApiDiff;
+import com.qdesrame.openapi.diff.core.model.Change;
+import com.qdesrame.openapi.diff.core.model.ChangedSchema;
+import com.qdesrame.openapi.diff.core.model.DiffContext;
+import com.qdesrame.openapi.diff.core.model.schema.*;
 import io.swagger.v3.oas.models.Components;
 import io.swagger.v3.oas.models.media.Schema;
 import java.util.*;

src/main/java/com/qdesrame/openapi/diff/model/Change.java → core/src/main/java/com/qdesrame/openapi/diff/core/model/Change.java

@@ -1,18 +1,13 @@
-package com.qdesrame.openapi.diff.model;
+package com.qdesrame.openapi.diff.core.model;
 
-import lombok.Getter;
+import lombok.Value;
 
-@Getter
+@Value
 public class Change<T> {
-  private final T oldValue;
-  private final T newValue;
-  private final Type type;
 
-  private Change(T oldValue, T newValue, Type type) {
-    this.oldValue = oldValue;
-    this.newValue = newValue;
-    this.type = type;
-  }
+  T oldValue;
+  T newValue;
+  Type type;
 
   public static <T> Change<T> changed(T oldValue, T newValue) {
     return new Change<>(oldValue, newValue, Type.CHANGED);

src/main/java/com/qdesrame/openapi/diff/model/Changed.java → core/src/main/java/com/qdesrame/openapi/diff/core/model/Changed.java

@@ -1,4 +1,4 @@
-package com.qdesrame.openapi.diff.model;
+package com.qdesrame.openapi.diff.core.model;
 
 import java.util.Optional;
 

src/main/java/com/qdesrame/openapi/diff/model/ChangedApiResponse.java → core/src/main/java/com/qdesrame/openapi/diff/core/model/ChangedApiResponse.java

@@ -1,4 +1,4 @@
-package com.qdesrame.openapi.diff.model;
+package com.qdesrame.openapi.diff.core.model;
 
 import io.swagger.v3.oas.models.responses.ApiResponse;
 import io.swagger.v3.oas.models.responses.ApiResponses;
@@ -7,15 +7,13 @@
 import java.util.Map;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
-import lombok.Getter;
-import lombok.Setter;
+import lombok.Data;
 import lombok.experimental.Accessors;
 
-/** Created by adarsh.sharma on 22/12/17. */
-@Getter
-@Setter
+@Data
 @Accessors(chain = true)
 public class ChangedApiResponse implements ComposedChanged {
+
   private final ApiResponses oldApiResponses;
   private final ApiResponses newApiResponses;
   private final DiffContext context;

src/main/java/com/qdesrame/openapi/diff/model/ChangedContent.java → core/src/main/java/com/qdesrame/openapi/diff/core/model/ChangedContent.java

@@ -1,20 +1,18 @@
-package com.qdesrame.openapi.diff.model;
+package com.qdesrame.openapi.diff.core.model;
 
 import io.swagger.v3.oas.models.media.Content;
 import io.swagger.v3.oas.models.media.MediaType;
 import java.util.ArrayList;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
-import lombok.Getter;
-import lombok.Setter;
+import lombok.Data;
 import lombok.experimental.Accessors;
 
-/** Created by adarsh.sharma on 22/12/17. */
-@Getter
-@Setter
+@Data
 @Accessors(chain = true)
 public class ChangedContent implements ComposedChanged {
+
   private final Content oldContent;
   private final Content newContent;
   private final DiffContext context;

src/main/java/com/qdesrame/openapi/diff/model/ChangedExtensions.java → core/src/main/java/com/qdesrame/openapi/diff/core/model/ChangedExtensions.java

@@ -1,19 +1,16 @@
-package com.qdesrame.openapi.diff.model;
+package com.qdesrame.openapi.diff.core.model;
 
 import java.util.Collection;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
-import lombok.Getter;
-import lombok.Setter;
-import lombok.experimental.Accessors;
+import lombok.Data;
 
-@Getter
-@Setter
-@Accessors
+@Data
 public class ChangedExtensions implements ComposedChanged {
+
   private final Map<String, Object> oldExtensions;
   private final Map<String, Object> newExtensions;
   private final DiffContext context;

src/main/java/com/qdesrame/openapi/diff/model/ChangedHeader.java → core/src/main/java/com/qdesrame/openapi/diff/core/model/ChangedHeader.java

@@ -1,17 +1,15 @@
-package com.qdesrame.openapi.diff.model;
+package com.qdesrame.openapi.diff.core.model;
 
 import io.swagger.v3.oas.models.headers.Header;
 import java.util.Arrays;
 import java.util.List;
-import lombok.Getter;
-import lombok.Setter;
+import lombok.Data;
 import lombok.experimental.Accessors;
 
-/** Created by adarsh.sharma on 28/12/17. */
-@Getter
-@Setter
+@Data
 @Accessors(chain = true)
 public class ChangedHeader implements ComposedChanged {
+
   private final Header oldHeader;
   private final Header newHeader;
   private final DiffContext context;

src/main/java/com/qdesrame/openapi/diff/model/ChangedHeaders.java → core/src/main/java/com/qdesrame/openapi/diff/core/model/ChangedHeaders.java

@@ -1,18 +1,16 @@
-package com.qdesrame.openapi.diff.model;
+package com.qdesrame.openapi.diff.core.model;
 
 import io.swagger.v3.oas.models.headers.Header;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
-import lombok.Getter;
-import lombok.Setter;
+import lombok.Data;
 import lombok.experimental.Accessors;
 
-/** Created by adarsh.sharma on 28/12/17. */
-@Getter
-@Setter
+@Data
 @Accessors(chain = true)
 public class ChangedHeaders implements ComposedChanged {
+
   private final Map<String, Header> oldHeaders;
   private final Map<String, Header> newHeaders;
   private final DiffContext context;

src/main/java/com/qdesrame/openapi/diff/model/ChangedList.java → core/src/main/java/com/qdesrame/openapi/diff/core/model/ChangedList.java

@@ -1,16 +1,15 @@
-package com.qdesrame.openapi.diff.model;
+package com.qdesrame.openapi.diff.core.model;
 
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Optional;
-import lombok.Getter;
-import lombok.Setter;
+import lombok.Data;
 import lombok.experimental.Accessors;
 
-@Getter
-@Setter
+@Data
 @Accessors(chain = true)
 public abstract class ChangedList<T> implements Changed {
+
   protected DiffContext context;
   protected List<T> oldValue;
   protected List<T> newValue;

src/main/java/com/qdesrame/openapi/diff/model/ChangedMediaType.java → core/src/main/java/com/qdesrame/openapi/diff/core/model/ChangedMediaType.java

@@ -1,16 +1,15 @@
-package com.qdesrame.openapi.diff.model;
+package com.qdesrame.openapi.diff.core.model;
 
 import io.swagger.v3.oas.models.media.Schema;
 import java.util.Collections;
 import java.util.List;
-import lombok.Getter;
-import lombok.Setter;
+import lombok.Data;
 import lombok.experimental.Accessors;
 
-@Getter
-@Setter
+@Data
 @Accessors(chain = true)
 public class ChangedMediaType implements ComposedChanged {
+
   private final Schema oldSchema;
   private final Schema newSchema;
   private final DiffContext context;

src/main/java/com/qdesrame/openapi/diff/model/ChangedMetadata.java → core/src/main/java/com/qdesrame/openapi/diff/core/model/ChangedMetadata.java

@@ -1,12 +1,10 @@
-package com.qdesrame.openapi.diff.model;
+package com.qdesrame.openapi.diff.core.model;
 
 import java.util.Objects;
-import lombok.Getter;
-import lombok.Setter;
+import lombok.Data;
 import lombok.experimental.Accessors;
 
-@Getter
-@Setter
+@Data
 @Accessors(chain = true)
 public class ChangedMetadata implements Changed {
 

src/main/java/com/qdesrame/openapi/diff/model/ChangedOAuthFlow.java → core/src/main/java/com/qdesrame/openapi/diff/core/model/ChangedOAuthFlow.java

@@ -1,17 +1,15 @@
-package com.qdesrame.openapi.diff.model;
+package com.qdesrame.openapi.diff.core.model;
 
 import io.swagger.v3.oas.models.security.OAuthFlow;
 import java.util.Collections;
 import java.util.List;
-import lombok.Getter;
-import lombok.Setter;
+import lombok.Data;
 import lombok.experimental.Accessors;
 
-/** Created by adarsh.sharma on 12/01/18. */
-@Getter
-@Setter
+@Data
 @Accessors(chain = true)
 public class ChangedOAuthFlow implements ComposedChanged {
+
   private OAuthFlow oldOAuthFlow;
   private OAuthFlow newOAuthFlow;
 

src/main/java/com/qdesrame/openapi/diff/model/ChangedOAuthFlows.java → core/src/main/java/com/qdesrame/openapi/diff/core/model/ChangedOAuthFlows.java

@@ -1,17 +1,15 @@
-package com.qdesrame.openapi.diff.model;
+package com.qdesrame.openapi.diff.core.model;
 
 import io.swagger.v3.oas.models.security.OAuthFlows;
 import java.util.Arrays;
 import java.util.List;
-import lombok.Getter;
-import lombok.Setter;
+import lombok.Data;
 import lombok.experimental.Accessors;
 
-/** Created by adarsh.sharma on 12/01/18. */
-@Getter
-@Setter
+@Data
 @Accessors(chain = true)
 public class ChangedOAuthFlows implements ComposedChanged {
+
   private final OAuthFlows oldOAuthFlows;
   private final OAuthFlows newOAuthFlows;
 

src/main/java/com/qdesrame/openapi/diff/model/ChangedOneOfSchema.java → core/src/main/java/com/qdesrame/openapi/diff/core/model/ChangedOneOfSchema.java

@@ -1,18 +1,16 @@
-package com.qdesrame.openapi.diff.model;
+package com.qdesrame.openapi.diff.core.model;
 
 import io.swagger.v3.oas.models.media.Schema;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
-import lombok.Getter;
-import lombok.Setter;
+import lombok.Data;
 import lombok.experimental.Accessors;
 
-/** Created by adarsh.sharma on 22/12/17. */
-@Getter
-@Setter
+@Data
 @Accessors(chain = true)
 public class ChangedOneOfSchema implements ComposedChanged {
+
   private final Map<String, String> oldMapping;
   private final Map<String, String> newMapping;
   private final DiffContext context;

src/main/java/com/qdesrame/openapi/diff/model/ChangedOpenApi.java → core/src/main/java/com/qdesrame/openapi/diff/core/model/ChangedOpenApi.java

@@ -1,19 +1,17 @@
-package com.qdesrame.openapi.diff.model;
+package com.qdesrame.openapi.diff.core.model;
 
-import com.qdesrame.openapi.diff.utils.EndpointUtils;
+import com.qdesrame.openapi.diff.core.utils.EndpointUtils;
 import io.swagger.v3.oas.models.OpenAPI;
 import java.util.List;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
-import lombok.Getter;
-import lombok.Setter;
+import lombok.Data;
 import lombok.experimental.Accessors;
 
-/** Created by adarsh.sharma on 22/12/17. */
-@Getter
-@Setter
+@Data
 @Accessors(chain = true)
 public class ChangedOpenApi implements ComposedChanged {
+
   private OpenAPI oldSpecOpenApi;
   private OpenAPI newSpecOpenApi;
 
@@ -23,8 +21,7 @@ public class ChangedOpenApi implements ComposedChanged {
   private ChangedExtensions changedExtensions;
 
   public List<Endpoint> getDeprecatedEndpoints() {
-    return changedOperations
-        .stream()
+    return changedOperations.stream()
         .filter(ChangedOperation::isDeprecated)
         .map(
             c ->

src/main/java/com/qdesrame/openapi/diff/model/ChangedOperation.java → core/src/main/java/com/qdesrame/openapi/diff/core/model/ChangedOperation.java

@@ -1,19 +1,18 @@
-package com.qdesrame.openapi.diff.model;
+package com.qdesrame.openapi.diff.core.model;
 
-import static com.qdesrame.openapi.diff.model.Changed.result;
+import static com.qdesrame.openapi.diff.core.model.Changed.result;
 
 import io.swagger.v3.oas.models.Operation;
 import io.swagger.v3.oas.models.PathItem;
 import java.util.Arrays;
 import java.util.List;
-import lombok.Getter;
-import lombok.Setter;
+import lombok.Data;
 import lombok.experimental.Accessors;
 
-@Getter
-@Setter
+@Data
 @Accessors(chain = true)
 public class ChangedOperation implements ComposedChanged {
+
   private Operation oldOperation;
   private Operation newOperation;
 

src/main/java/com/qdesrame/openapi/diff/model/ChangedParameter.java → core/src/main/java/com/qdesrame/openapi/diff/core/model/ChangedParameter.java

@@ -1,16 +1,15 @@
-package com.qdesrame.openapi.diff.model;
+package com.qdesrame.openapi.diff.core.model;
 
 import io.swagger.v3.oas.models.parameters.Parameter;
 import java.util.Arrays;
 import java.util.List;
-import lombok.Getter;
-import lombok.Setter;
+import lombok.Data;
 import lombok.experimental.Accessors;
 
-@Getter
-@Setter
+@Data
 @Accessors(chain = true)
 public class ChangedParameter implements ComposedChanged {
+
   private final DiffContext context;
   private Parameter oldParameter;
   private Parameter newParameter;

src/main/java/com/qdesrame/openapi/diff/model/ChangedParameters.java → core/src/main/java/com/qdesrame/openapi/diff/core/model/ChangedParameters.java

@@ -1,14 +1,12 @@
-package com.qdesrame.openapi.diff.model;
+package com.qdesrame.openapi.diff.core.model;
 
 import io.swagger.v3.oas.models.parameters.Parameter;
 import java.util.ArrayList;
 import java.util.List;
-import lombok.Getter;
-import lombok.Setter;
+import lombok.Data;
 import lombok.experimental.Accessors;
 
-@Getter
-@Setter
+@Data
 @Accessors(chain = true)
 public class ChangedParameters implements ComposedChanged {
   private final List<Parameter> oldParameterList;
@@ -39,7 +37,12 @@ public DiffResult isCoreChanged() {
     if (increased.isEmpty() && missing.isEmpty()) {
       return DiffResult.NO_CHANGES;
     }
-    if (increased.stream().noneMatch(Parameter::getRequired) && missing.isEmpty()) {
+    if (increased.stream()
+            .noneMatch(
+                p -> {
+                  return p.getRequired() != null && p.getRequired();
+                })
+        && missing.isEmpty()) {
       return DiffResult.COMPATIBLE;
     }
     return DiffResult.INCOMPATIBLE;

src/main/java/com/qdesrame/openapi/diff/model/ChangedPath.java → core/src/main/java/com/qdesrame/openapi/diff/core/model/ChangedPath.java

@@ -1,4 +1,4 @@
-package com.qdesrame.openapi.diff.model;
+package com.qdesrame.openapi.diff.core.model;
 
 import io.swagger.v3.oas.models.Operation;
 import io.swagger.v3.oas.models.PathItem;
@@ -8,14 +8,13 @@
 import java.util.Map;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
-import lombok.Getter;
-import lombok.Setter;
+import lombok.Data;
 import lombok.experimental.Accessors;
 
-@Getter
-@Setter
+@Data
 @Accessors(chain = true)
 public class ChangedPath implements ComposedChanged {
+
   private final String pathUrl;
   private final PathItem oldPath;
   private final PathItem newPath;

src/main/java/com/qdesrame/openapi/diff/model/ChangedPaths.java → core/src/main/java/com/qdesrame/openapi/diff/core/model/ChangedPaths.java

@@ -1,16 +1,15 @@
-package com.qdesrame.openapi.diff.model;
+package com.qdesrame.openapi.diff.core.model;
 
 import io.swagger.v3.oas.models.PathItem;
 import java.util.ArrayList;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
-import lombok.Getter;
-import lombok.Setter;
+import lombok.Data;
 
-@Getter
-@Setter
+@Data
 public class ChangedPaths implements ComposedChanged {
+
   private final Map<String, PathItem> oldPathMap;
   private final Map<String, PathItem> newPathMap;
 

src/main/java/com/qdesrame/openapi/diff/model/ChangedRequestBody.java → core/src/main/java/com/qdesrame/openapi/diff/core/model/ChangedRequestBody.java

@@ -1,17 +1,15 @@
-package com.qdesrame.openapi.diff.model;
+package com.qdesrame.openapi.diff.core.model;
 
 import io.swagger.v3.oas.models.parameters.RequestBody;
 import java.util.Arrays;
 import java.util.List;
-import lombok.Getter;
-import lombok.Setter;
+import lombok.Data;
 import lombok.experimental.Accessors;
 
-/** Created by adarsh.sharma on 27/12/17. */
-@Getter
-@Setter
+@Data
 @Accessors(chain = true)
 public class ChangedRequestBody implements ComposedChanged {
+
   private final RequestBody oldRequestBody;
   private final RequestBody newRequestBody;
   private final DiffContext context;

src/main/java/com/qdesrame/openapi/diff/model/ChangedResponse.java → core/src/main/java/com/qdesrame/openapi/diff/core/model/ChangedResponse.java

@@ -1,16 +1,15 @@
-package com.qdesrame.openapi.diff.model;
+package com.qdesrame.openapi.diff.core.model;
 
 import io.swagger.v3.oas.models.responses.ApiResponse;
 import java.util.Arrays;
 import java.util.List;
-import lombok.Getter;
-import lombok.Setter;
+import lombok.Data;
 import lombok.experimental.Accessors;
 
-@Getter
-@Setter
+@Data
 @Accessors(chain = true)
 public class ChangedResponse implements ComposedChanged {
+
   private final ApiResponse oldApiResponse;
   private final ApiResponse newApiResponse;
   private final DiffContext context;

src/main/java/com/qdesrame/openapi/diff/model/ChangedSchema.java → core/src/main/java/com/qdesrame/openapi/diff/core/model/ChangedSchema.java

@@ -1,21 +1,24 @@
-package com.qdesrame.openapi.diff.model;
+package com.qdesrame.openapi.diff.core.model;
 
-import com.qdesrame.openapi.diff.model.schema.*;
+import com.qdesrame.openapi.diff.core.model.schema.ChangedEnum;
+import com.qdesrame.openapi.diff.core.model.schema.ChangedMaxLength;
+import com.qdesrame.openapi.diff.core.model.schema.ChangedReadOnly;
+import com.qdesrame.openapi.diff.core.model.schema.ChangedRequired;
+import com.qdesrame.openapi.diff.core.model.schema.ChangedWriteOnly;
+import io.swagger.v3.oas.models.PathItem;
 import io.swagger.v3.oas.models.media.Schema;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
-import lombok.Getter;
-import lombok.Setter;
+import lombok.Data;
 import lombok.experimental.Accessors;
 
-/** Created by adarsh.sharma on 22/12/17. */
-@Getter
-@Setter
+@Data
 @Accessors(chain = true)
 public class ChangedSchema implements ComposedChanged {
+
   protected DiffContext context;
   protected Schema oldSchema;
   protected Schema newSchema;
@@ -76,15 +79,24 @@ public DiffResult isCoreChanged() {
         && !discriminatorPropertyChanged) {
       return DiffResult.NO_CHANGES;
     }
-    boolean compatibleForRequest = (oldSchema != null || newSchema == null);
     boolean compatibleForResponse =
         missingProperties.isEmpty() && (oldSchema == null || newSchema != null);
-    if ((context.isRequest() && compatibleForRequest
+    if ((context.isRequest() && compatibleForRequest()
             || context.isResponse() && compatibleForResponse)
         && !changedType
         && !discriminatorPropertyChanged) {
       return DiffResult.COMPATIBLE;
     }
     return DiffResult.INCOMPATIBLE;
   }
+
+  private boolean compatibleForRequest() {
+    if (PathItem.HttpMethod.PUT.equals(context.getMethod())) {
+      if (increasedProperties.size() > 0) {
+        return false;
+      }
+    }
+
+    return (oldSchema != null || newSchema == null);
+  }
 }

src/main/java/com/qdesrame/openapi/diff/model/ChangedSecurityRequirement.java → core/src/main/java/com/qdesrame/openapi/diff/core/model/ChangedSecurityRequirement.java

@@ -1,17 +1,15 @@
-package com.qdesrame.openapi.diff.model;
+package com.qdesrame.openapi.diff.core.model;
 
 import io.swagger.v3.oas.models.security.SecurityRequirement;
 import java.util.ArrayList;
 import java.util.List;
-import lombok.Getter;
-import lombok.Setter;
+import lombok.Data;
 import lombok.experimental.Accessors;
 
-/** Created by adarsh.sharma on 06/01/18. */
-@Getter
-@Setter
+@Data
 @Accessors(chain = true)
 public class ChangedSecurityRequirement implements ComposedChanged {
+
   private SecurityRequirement oldSecurityRequirement;
   private SecurityRequirement newSecurityRequirement;
 

src/main/java/com/qdesrame/openapi/diff/model/ChangedSecurityRequirements.java → core/src/main/java/com/qdesrame/openapi/diff/core/model/ChangedSecurityRequirements.java

@@ -1,18 +1,16 @@
-package com.qdesrame.openapi.diff.model;
+package com.qdesrame.openapi.diff.core.model;
 
 import io.swagger.v3.oas.models.security.SecurityRequirement;
 import java.util.ArrayList;
 import java.util.List;
-import lombok.Getter;
-import lombok.Setter;
+import lombok.Data;
 import lombok.experimental.Accessors;
 import org.apache.commons.collections4.CollectionUtils;
 
-/** Created by adarsh.sharma on 06/01/18. */
-@Getter
-@Setter
+@Data
 @Accessors(chain = true)
 public class ChangedSecurityRequirements implements ComposedChanged {
+
   private List<SecurityRequirement> oldSecurityRequirements;
   private List<SecurityRequirement> newSecurityRequirements;
 

src/main/java/com/qdesrame/openapi/diff/model/ChangedSecurityScheme.java → core/src/main/java/com/qdesrame/openapi/diff/core/model/ChangedSecurityScheme.java

@@ -1,17 +1,16 @@
-package com.qdesrame.openapi.diff.model;
+package com.qdesrame.openapi.diff.core.model;
 
 import io.swagger.v3.oas.models.security.SecurityScheme;
 import java.util.Arrays;
 import java.util.List;
-import lombok.Getter;
-import lombok.Setter;
+import lombok.Data;
 import lombok.experimental.Accessors;
 
 /** Created by adarsh.sharma on 11/01/18. */
-@Getter
-@Setter
+@Data
 @Accessors(chain = true)
 public class ChangedSecurityScheme implements ComposedChanged {
+
   private SecurityScheme oldSecurityScheme;
   private SecurityScheme newSecurityScheme;
 

src/main/java/com/qdesrame/openapi/diff/model/ChangedSecuritySchemeScopes.java → core/src/main/java/com/qdesrame/openapi/diff/core/model/ChangedSecuritySchemeScopes.java

@@ -1,9 +1,7 @@
-package com.qdesrame.openapi.diff.model;
+package com.qdesrame.openapi.diff.core.model;
 
 import java.util.List;
-import lombok.Getter;
 
-@Getter
 public class ChangedSecuritySchemeScopes extends ChangedList<String> {
 
   public ChangedSecuritySchemeScopes(List<String> oldValue, List<String> newValue) {

src/main/java/com/qdesrame/openapi/diff/model/ComposedChanged.java → core/src/main/java/com/qdesrame/openapi/diff/core/model/ComposedChanged.java

@@ -1,4 +1,4 @@
-package com.qdesrame.openapi.diff.model;
+package com.qdesrame.openapi.diff.core.model;
 
 import java.util.List;
 import java.util.Objects;
@@ -16,8 +16,7 @@ public interface ComposedChanged extends Changed {
   default DiffResult isChanged() {
     DiffResult elementsResult =
         DiffResult.fromWeight(
-            getChangedElements()
-                .stream()
+            getChangedElements().stream()
                 .filter(Objects::nonNull)
                 .map(Changed::isChanged)
                 .mapToInt(DiffResult::getWeight)

src/main/java/com/qdesrame/openapi/diff/model/DiffContext.java → core/src/main/java/com/qdesrame/openapi/diff/core/model/DiffContext.java

@@ -1,4 +1,4 @@
-package com.qdesrame.openapi.diff.model;
+package com.qdesrame.openapi.diff.core.model;
 
 import io.swagger.v3.oas.models.PathItem;
 import java.util.HashMap;

src/main/java/com/qdesrame/openapi/diff/model/DiffResult.java → core/src/main/java/com/qdesrame/openapi/diff/core/model/DiffResult.java

@@ -1,4 +1,4 @@
-package com.qdesrame.openapi.diff.model;
+package com.qdesrame.openapi.diff.core.model;
 
 import static java.lang.String.format;
 

src/main/java/com/qdesrame/openapi/diff/model/Endpoint.java → core/src/main/java/com/qdesrame/openapi/diff/core/model/Endpoint.java

@@ -1,12 +1,10 @@
-package com.qdesrame.openapi.diff.model;
+package com.qdesrame.openapi.diff.core.model;
 
 import io.swagger.v3.oas.models.Operation;
 import io.swagger.v3.oas.models.PathItem;
-import lombok.Getter;
-import lombok.Setter;
+import lombok.Data;
 
-@Getter
-@Setter
+@Data
 public class Endpoint {
 
   private String pathUrl;

src/main/java/com/qdesrame/openapi/diff/model/schema/ChangedEnum.java → core/src/main/java/com/qdesrame/openapi/diff/core/model/schema/ChangedEnum.java

@@ -1,12 +1,10 @@
-package com.qdesrame.openapi.diff.model.schema;
+package com.qdesrame.openapi.diff.core.model.schema;
 
-import com.qdesrame.openapi.diff.model.ChangedList;
-import com.qdesrame.openapi.diff.model.DiffContext;
-import com.qdesrame.openapi.diff.model.DiffResult;
+import com.qdesrame.openapi.diff.core.model.ChangedList;
+import com.qdesrame.openapi.diff.core.model.DiffContext;
+import com.qdesrame.openapi.diff.core.model.DiffResult;
 import java.util.List;
-import lombok.Getter;
 
-@Getter
 public class ChangedEnum<T> extends ChangedList<T> {
 
   public ChangedEnum(List<T> oldValue, List<T> newValue, DiffContext context) {

src/main/java/com/qdesrame/openapi/diff/model/schema/ChangedMaxLength.java → core/src/main/java/com/qdesrame/openapi/diff/core/model/schema/ChangedMaxLength.java

@@ -1,20 +1,17 @@
-package com.qdesrame.openapi.diff.model.schema;
+package com.qdesrame.openapi.diff.core.model.schema;
 
-import com.qdesrame.openapi.diff.model.Changed;
-import com.qdesrame.openapi.diff.model.DiffContext;
-import com.qdesrame.openapi.diff.model.DiffResult;
+import com.qdesrame.openapi.diff.core.model.Changed;
+import com.qdesrame.openapi.diff.core.model.DiffContext;
+import com.qdesrame.openapi.diff.core.model.DiffResult;
 import java.util.Objects;
+import lombok.Value;
 
+@Value
 public class ChangedMaxLength implements Changed {
-  private final Integer oldValue;
-  private final Integer newValue;
-  private final DiffContext context;
 
-  public ChangedMaxLength(Integer oldValue, Integer newValue, DiffContext context) {
-    this.oldValue = oldValue;
-    this.newValue = newValue;
-    this.context = context;
-  }
+  Integer oldValue;
+  Integer newValue;
+  DiffContext context;
 
   @Override
   public DiffResult isChanged() {

src/main/java/com/qdesrame/openapi/diff/model/schema/ChangedReadOnly.java → core/src/main/java/com/qdesrame/openapi/diff/core/model/schema/ChangedReadOnly.java

@@ -1,8 +1,8 @@
-package com.qdesrame.openapi.diff.model.schema;
+package com.qdesrame.openapi.diff.core.model.schema;
 
-import com.qdesrame.openapi.diff.model.Changed;
-import com.qdesrame.openapi.diff.model.DiffContext;
-import com.qdesrame.openapi.diff.model.DiffResult;
+import com.qdesrame.openapi.diff.core.model.Changed;
+import com.qdesrame.openapi.diff.core.model.DiffContext;
+import com.qdesrame.openapi.diff.core.model.DiffResult;
 import java.util.Objects;
 import java.util.Optional;
 

src/main/java/com/qdesrame/openapi/diff/model/schema/ChangedRequired.java → core/src/main/java/com/qdesrame/openapi/diff/core/model/schema/ChangedRequired.java

@@ -1,12 +1,10 @@
-package com.qdesrame.openapi.diff.model.schema;
+package com.qdesrame.openapi.diff.core.model.schema;
 
-import com.qdesrame.openapi.diff.model.ChangedList;
-import com.qdesrame.openapi.diff.model.DiffContext;
-import com.qdesrame.openapi.diff.model.DiffResult;
+import com.qdesrame.openapi.diff.core.model.ChangedList;
+import com.qdesrame.openapi.diff.core.model.DiffContext;
+import com.qdesrame.openapi.diff.core.model.DiffResult;
 import java.util.List;
-import lombok.Getter;
 
-@Getter
 public class ChangedRequired extends ChangedList<String> {
 
   public ChangedRequired(List<String> oldValue, List<String> newValue, DiffContext context) {

src/main/java/com/qdesrame/openapi/diff/model/schema/ChangedWriteOnly.java → core/src/main/java/com/qdesrame/openapi/diff/core/model/schema/ChangedWriteOnly.java

@@ -1,8 +1,8 @@
-package com.qdesrame.openapi.diff.model.schema;
+package com.qdesrame.openapi.diff.core.model.schema;
 
-import com.qdesrame.openapi.diff.model.Changed;
-import com.qdesrame.openapi.diff.model.DiffContext;
-import com.qdesrame.openapi.diff.model.DiffResult;
+import com.qdesrame.openapi.diff.core.model.Changed;
+import com.qdesrame.openapi.diff.core.model.DiffContext;
+import com.qdesrame.openapi.diff.core.model.DiffResult;
 import java.util.Objects;
 import java.util.Optional;
 

src/main/java/com/qdesrame/openapi/diff/output/ConsoleRender.java → core/src/main/java/com/qdesrame/openapi/diff/core/output/ConsoleRender.java

@@ -1,10 +1,10 @@
-package com.qdesrame.openapi.diff.output;
+package com.qdesrame.openapi.diff.core.output;
 
-import static com.qdesrame.openapi.diff.model.Changed.result;
+import static com.qdesrame.openapi.diff.core.model.Changed.result;
 
-import com.qdesrame.openapi.diff.model.*;
-import com.qdesrame.openapi.diff.utils.RefPointer;
-import com.qdesrame.openapi.diff.utils.RefType;
+import com.qdesrame.openapi.diff.core.model.*;
+import com.qdesrame.openapi.diff.core.utils.RefPointer;
+import com.qdesrame.openapi.diff.core.utils.RefType;
 import io.swagger.v3.oas.models.media.ArraySchema;
 import io.swagger.v3.oas.models.media.Schema;
 import io.swagger.v3.oas.models.parameters.Parameter;
@@ -213,12 +213,19 @@ private String properties(
       String propPrefix, String title, Map<String, Schema> properties, DiffContext context) {
     StringBuilder sb = new StringBuilder();
     if (properties != null) {
-      properties.forEach(
-          (key, value) -> sb.append(property(propPrefix + key, title, resolve(value))));
+      properties.forEach((key, value) -> sb.append(resolveProperty(propPrefix, value, key, title)));
     }
     return sb.toString();
   }
 
+  private String resolveProperty(String propPrefix, Schema value, String key, String title) {
+    try {
+      return property(propPrefix + key, title, resolve(value));
+    } catch (Exception e) {
+      return property(propPrefix + key, title, type(value));
+    }
+  }
+
   protected String property(String name, String title, Schema schema) {
     return property(name, title, type(schema));
   }
@@ -234,7 +241,9 @@ protected Schema resolve(Schema schema) {
 
   protected String type(Schema schema) {
     String result = "object";
-    if (schema instanceof ArraySchema) {
+    if (schema == null) {
+      result = "no schema";
+    } else if (schema instanceof ArraySchema) {
       result = "array";
     } else if (schema.getType() != null) {
       result = schema.getType();

src/main/java/com/qdesrame/openapi/diff/output/HtmlRender.java → core/src/main/java/com/qdesrame/openapi/diff/core/output/HtmlRender.java

@@ -1,11 +1,11 @@
-package com.qdesrame.openapi.diff.output;
+package com.qdesrame.openapi.diff.core.output;
 
-import static com.qdesrame.openapi.diff.model.Changed.result;
+import static com.qdesrame.openapi.diff.core.model.Changed.result;
 import static j2html.TagCreator.*;
 
-import com.qdesrame.openapi.diff.model.*;
-import com.qdesrame.openapi.diff.utils.RefPointer;
-import com.qdesrame.openapi.diff.utils.RefType;
+import com.qdesrame.openapi.diff.core.model.*;
+import com.qdesrame.openapi.diff.core.utils.RefPointer;
+import com.qdesrame.openapi.diff.core.utils.RefType;
 import io.swagger.v3.oas.models.media.ArraySchema;
 import io.swagger.v3.oas.models.media.MediaType;
 import io.swagger.v3.oas.models.media.Schema;
@@ -269,7 +269,16 @@ private void properties(
       Map<String, Schema> properties,
       DiffContext context) {
     if (properties != null) {
-      properties.forEach((key, value) -> property(output, propPrefix + key, title, resolve(value)));
+      properties.forEach((key, value) -> resolveProperty(output, propPrefix, key, value, title));
+    }
+  }
+
+  private void resolveProperty(
+      ContainerTag output, String propPrefix, String key, Schema value, String title) {
+    try {
+      property(output, propPrefix + key, title, resolve(value));
+    } catch (Exception e) {
+      property(output, propPrefix + key, title, type(value));
     }
   }
 
@@ -288,7 +297,9 @@ protected Schema resolve(Schema schema) {
 
   protected String type(Schema schema) {
     String result = "object";
-    if (schema instanceof ArraySchema) {
+    if (schema == null) {
+      result = "no schema";
+    } else if (schema instanceof ArraySchema) {
       result = "array";
     } else if (schema.getType() != null) {
       result = schema.getType();
@@ -347,7 +358,10 @@ private ContainerTag li_changedParam(ChangedParameter changeParam) {
       return li_deprecatedParam(changeParam);
     }
     boolean changeRequired = changeParam.isChangeRequired();
-    boolean changeDescription = changeParam.getDescription().isDifferent();
+    boolean changeDescription =
+        Optional.ofNullable(changeParam.getDescription())
+            .map(ChangedMetadata::isDifferent)
+            .orElse(false);
     Parameter rightParam = changeParam.getNewParameter();
     Parameter leftParam = changeParam.getNewParameter();
     ContainerTag li = li().withText(changeParam.getName() + " in " + changeParam.getIn());

src/main/java/com/qdesrame/openapi/diff/output/MarkdownRender.java → core/src/main/java/com/qdesrame/openapi/diff/core/output/MarkdownRender.java

@@ -1,12 +1,12 @@
-package com.qdesrame.openapi.diff.output;
+package com.qdesrame.openapi.diff.core.output;
 
-import static com.qdesrame.openapi.diff.model.Changed.result;
-import static com.qdesrame.openapi.diff.utils.ChangedUtils.isUnchanged;
+import static com.qdesrame.openapi.diff.core.model.Changed.result;
+import static com.qdesrame.openapi.diff.core.utils.ChangedUtils.isUnchanged;
 import static java.lang.String.format;
 
-import com.qdesrame.openapi.diff.model.*;
-import com.qdesrame.openapi.diff.utils.RefPointer;
-import com.qdesrame.openapi.diff.utils.RefType;
+import com.qdesrame.openapi.diff.core.model.*;
+import com.qdesrame.openapi.diff.core.utils.RefPointer;
+import com.qdesrame.openapi.diff.core.utils.RefType;
 import io.swagger.v3.oas.models.headers.Header;
 import io.swagger.v3.oas.models.media.ArraySchema;
 import io.swagger.v3.oas.models.media.ComposedSchema;
@@ -63,8 +63,7 @@ protected String sectionTitle(String title) {
   protected String listEndpoints(String title, List<Endpoint> endpoints) {
     if (null == endpoints || endpoints.size() == 0) return "";
     StringBuilder sb = new StringBuilder(sectionTitle(title));
-    endpoints
-        .stream()
+    endpoints.stream()
         .map(e -> itemEndpoint(e.getMethod().toString(), e.getPathUrl(), e.getSummary()))
         .forEach(sb::append);
     return sb.toString();
@@ -85,8 +84,7 @@ protected String titleH5(String title) {
   protected String listEndpoints(List<ChangedOperation> changedOperations) {
     if (null == changedOperations || changedOperations.size() == 0) return "";
     StringBuilder sb = new StringBuilder(sectionTitle("What's Changed"));
-    changedOperations
-        .stream()
+    changedOperations.stream()
         .map(
             operation -> {
               StringBuilder details =
@@ -122,20 +120,15 @@ protected String responses(ChangedApiResponse changedApiResponse) {
     StringBuilder sb = new StringBuilder("\n");
     sb.append(listResponse("New response", changedApiResponse.getIncreased()));
     sb.append(listResponse("Deleted response", changedApiResponse.getMissing()));
-    changedApiResponse
-        .getChanged()
-        .entrySet()
-        .stream()
+    changedApiResponse.getChanged().entrySet().stream()
         .map(e -> this.itemResponse(e.getKey(), e.getValue()))
         .forEach(sb::append);
     return sb.toString();
   }
 
   protected String listResponse(String title, Map<String, ApiResponse> responses) {
     StringBuilder sb = new StringBuilder();
-    responses
-        .entrySet()
-        .stream()
+    responses.entrySet().stream()
         .map(e -> this.itemResponse(title, e.getKey(), e.getValue()))
         .forEach(sb::append);
     return sb.toString();
@@ -177,10 +170,7 @@ protected String headers(ChangedHeaders headers) {
     if (headers != null) {
       sb.append(listHeader("New header", headers.getIncreased()))
           .append(listHeader("Deleted header", headers.getMissing()));
-      headers
-          .getChanged()
-          .entrySet()
-          .stream()
+      headers.getChanged().entrySet().stream()
           .map(e -> this.itemHeader(e.getKey(), e.getValue()))
           .forEach(sb::append);
     }
@@ -189,9 +179,7 @@ protected String headers(ChangedHeaders headers) {
 
   protected String listHeader(String title, Map<String, Header> headers) {
     StringBuilder sb = new StringBuilder();
-    headers
-        .entrySet()
-        .stream()
+    headers.entrySet().stream()
         .map(e -> this.itemHeader(title, e.getKey(), e.getValue()))
         .forEach(sb::append);
     return sb.toString();
@@ -225,10 +213,7 @@ protected String bodyContent(String prefix, ChangedContent changedContent) {
     } else {
       deepness = 0;
     }
-    changedContent
-        .getChanged()
-        .entrySet()
-        .stream()
+    changedContent.getChanged().entrySet().stream()
         .map(e -> this.itemContent(deepness, e.getKey(), e.getValue()))
         .forEach(e -> sb.append(prefix).append(e));
     return sb.toString();
@@ -240,9 +225,7 @@ protected String bodyContent(ChangedContent changedContent) {
 
   protected String listContent(String prefix, String title, Map<String, MediaType> mediaTypes) {
     StringBuilder sb = new StringBuilder();
-    mediaTypes
-        .entrySet()
-        .stream()
+    mediaTypes.entrySet().stream()
         .map(e -> this.itemContent(title, e.getKey(), e.getValue()))
         .forEach(e -> sb.append(prefix).append(e));
     return sb.toString();
@@ -340,18 +323,14 @@ protected String schema(int deepness, ComposedSchema schema, DiffContext context
     StringBuilder sb = new StringBuilder();
     if (schema.getAllOf() != null && schema.getAllOf() != null) {
       LOGGER.debug("All of schema");
-      schema
-          .getAllOf()
-          .stream()
+      schema.getAllOf().stream()
           .map(this::resolve)
           .forEach(composedChild -> sb.append(schema(deepness, composedChild, context)));
     }
     if (schema.getOneOf() != null && schema.getOneOf() != null) {
       LOGGER.debug("One of schema");
       sb.append(format("%sOne of:\n\n", indent(deepness)));
-      schema
-          .getOneOf()
-          .stream()
+      schema.getOneOf().stream()
           .map(this::resolve)
           .forEach(composedChild -> sb.append(schema(deepness + 1, composedChild, context)));
     }
@@ -402,7 +381,7 @@ protected String properties(
     if (properties != null) {
       properties.forEach(
           (key, value) -> {
-            sb.append(property(deepness, title, key, resolve(value)));
+            sb.append(resolveProperty(deepness, value, key, title));
             if (showContent) {
               sb.append(schema(deepness + 1, resolve(value), context));
             }
@@ -411,6 +390,14 @@ protected String properties(
     return sb.toString();
   }
 
+  private String resolveProperty(int deepness, Schema value, String key, String title) {
+    try {
+      return property(deepness, title, key, resolve(value));
+    } catch (Exception e) {
+      return property(deepness, title, key, type(value), "");
+    }
+  }
+
   protected String property(int deepness, String name, ChangedSchema schema) {
     StringBuilder sb = new StringBuilder();
     String type = type(schema.getNewSchema());

core/src/main/java/com/qdesrame/openapi/diff/core/output/Render.java

@@ -0,0 +1,8 @@
+package com.qdesrame.openapi.diff.core.output;
+
+import com.qdesrame.openapi.diff.core.model.ChangedOpenApi;
+
+public interface Render {
+
+  String render(ChangedOpenApi diff);
+}

src/main/java/com/qdesrame/openapi/diff/utils/ChangedUtils.java → core/src/main/java/com/qdesrame/openapi/diff/core/utils/ChangedUtils.java

@@ -1,6 +1,6 @@
-package com.qdesrame.openapi.diff.utils;
+package com.qdesrame.openapi.diff.core.utils;
 
-import com.qdesrame.openapi.diff.model.Changed;
+import com.qdesrame.openapi.diff.core.model.Changed;
 import java.util.Optional;
 
 public class ChangedUtils {

src/main/java/com/qdesrame/openapi/diff/utils/Copy.java → core/src/main/java/com/qdesrame/openapi/diff/core/utils/Copy.java

@@ -1,4 +1,4 @@
-package com.qdesrame.openapi.diff.utils;
+package com.qdesrame.openapi.diff.core.utils;
 
 import java.util.LinkedHashMap;
 import java.util.Map;

src/main/java/com/qdesrame/openapi/diff/utils/EndpointUtils.java → core/src/main/java/com/qdesrame/openapi/diff/core/utils/EndpointUtils.java

@@ -1,6 +1,6 @@
-package com.qdesrame.openapi.diff.utils;
+package com.qdesrame.openapi.diff.core.utils;
 
-import com.qdesrame.openapi.diff.model.Endpoint;
+import com.qdesrame.openapi.diff.core.model.Endpoint;
 import io.swagger.v3.oas.models.Operation;
 import io.swagger.v3.oas.models.PathItem;
 import java.util.ArrayList;

src/main/java/com/qdesrame/openapi/diff/utils/RefPointer.java → core/src/main/java/com/qdesrame/openapi/diff/core/utils/RefPointer.java

@@ -1,4 +1,4 @@
-package com.qdesrame.openapi.diff.utils;
+package com.qdesrame.openapi.diff.core.utils;
 
 import io.swagger.v3.oas.models.Components;
 import java.util.Map;

src/main/java/com/qdesrame/openapi/diff/utils/RefType.java → core/src/main/java/com/qdesrame/openapi/diff/core/utils/RefType.java

@@ -1,8 +1,7 @@
-package com.qdesrame.openapi.diff.utils;
+package com.qdesrame.openapi.diff.core.utils;
 
 import lombok.Getter;
 
-/** Created by adarsh.sharma on 07/01/18. */
 @Getter
 public enum RefType {
   REQUEST_BODIES("requestBodies"),
@@ -17,5 +16,5 @@ public enum RefType {
     this.name = name;
   }
 
-  private String name;
+  private final String name;
 }

core/src/test/java/com/qdesrame/openapi/test/AddPropPutDiffTest.java

@@ -0,0 +1,22 @@
+package com.qdesrame.openapi.test;
+
+import static com.qdesrame.openapi.test.TestUtils.assertOpenApiAreEquals;
+import static com.qdesrame.openapi.test.TestUtils.assertOpenApiBackwardIncompatible;
+
+import org.junit.jupiter.api.Test;
+
+/** Created by trohrberg on 23/03/19. */
+public class AddPropPutDiffTest {
+  private final String OPENAPI_DOC1 = "add-prop-put-1.yaml";
+  private final String OPENAPI_DOC2 = "add-prop-put-2.yaml";
+
+  @Test
+  public void testDiffSame() {
+    assertOpenApiAreEquals(OPENAPI_DOC1, OPENAPI_DOC1);
+  }
+
+  @Test
+  public void testDiffDifferent() {
+    assertOpenApiBackwardIncompatible(OPENAPI_DOC1, OPENAPI_DOC2);
+  }
+}

core/src/test/java/com/qdesrame/openapi/test/ConsoleRenderTest.java

@@ -0,0 +1,18 @@
+package com.qdesrame.openapi.test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import com.qdesrame.openapi.diff.core.OpenApiCompare;
+import com.qdesrame.openapi.diff.core.model.ChangedOpenApi;
+import com.qdesrame.openapi.diff.core.output.ConsoleRender;
+import org.junit.jupiter.api.Test;
+
+public class ConsoleRenderTest {
+  @Test
+  public void renderDoesNotFailWhenPropertyHasBeenRemoved() {
+    ConsoleRender render = new ConsoleRender();
+    ChangedOpenApi diff =
+        OpenApiCompare.fromLocations("missing_property_1.yaml", "missing_property_2.yaml");
+    assertThat(render.render(diff)).isNotBlank();
+  }
+}

src/test/java/com/qdesrame/openapi/test/ContentDiffTest.java → core/src/test/java/com/qdesrame/openapi/test/ContentDiffTest.java

@@ -2,8 +2,8 @@
 
 import static org.assertj.core.api.Assertions.assertThat;
 
-import com.qdesrame.openapi.diff.OpenApiCompare;
-import com.qdesrame.openapi.diff.model.ChangedOpenApi;
+import com.qdesrame.openapi.diff.core.OpenApiCompare;
+import com.qdesrame.openapi.diff.core.model.ChangedOpenApi;
 import org.junit.jupiter.api.Test;
 
 public class ContentDiffTest {

core/src/test/java/com/qdesrame/openapi/test/HtmlRenderTest.java

@@ -0,0 +1,18 @@
+package com.qdesrame.openapi.test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import com.qdesrame.openapi.diff.core.OpenApiCompare;
+import com.qdesrame.openapi.diff.core.model.ChangedOpenApi;
+import com.qdesrame.openapi.diff.core.output.HtmlRender;
+import org.junit.jupiter.api.Test;
+
+public class HtmlRenderTest {
+  @Test
+  public void renderDoesNotFailWhenPropertyHasBeenRemoved() {
+    HtmlRender render = new HtmlRender();
+    ChangedOpenApi diff =
+        OpenApiCompare.fromLocations("missing_property_1.yaml", "missing_property_2.yaml");
+    assertThat(render.render(diff)).isNotBlank();
+  }
+}

core/src/test/java/com/qdesrame/openapi/test/MarkdownRenderTest.java

@@ -0,0 +1,18 @@
+package com.qdesrame.openapi.test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import com.qdesrame.openapi.diff.core.OpenApiCompare;
+import com.qdesrame.openapi.diff.core.model.ChangedOpenApi;
+import com.qdesrame.openapi.diff.core.output.MarkdownRender;
+import org.junit.jupiter.api.Test;
+
+public class MarkdownRenderTest {
+  @Test
+  public void renderDoesNotFailWhenPropertyHasBeenRemoved() {
+    MarkdownRender render = new MarkdownRender();
+    ChangedOpenApi diff =
+        OpenApiCompare.fromLocations("missing_property_1.yaml", "missing_property_2.yaml");
+    assertThat(render.render(diff)).isNotBlank();
+  }
+}

src/test/java/com/qdesrame/openapi/test/OneOfDiffTest.java → core/src/test/java/com/qdesrame/openapi/test/OneOfDiffTest.java

@@ -16,6 +16,8 @@ public class OneOfDiffTest {
   private final String OPENAPI_DOC5 = "composed_schema_2.yaml";
   private final String OPENAPI_DOC6 = "oneOf_discriminator-changed_1.yaml";
   private final String OPENAPI_DOC7 = "oneOf_discriminator-changed_2.yaml";
+  private final String OPENAPI_DOC8 = "oneOf_discriminator-missing_1.yaml";
+  private final String OPENAPI_DOC9 = "oneOf_discriminator-missing_2.yaml";
 
   @Test
   public void testDiffSame() {
@@ -42,4 +44,14 @@ public void testOneOfDiscrimitatorChanged() {
     // The oneOf 'discriminator' changed: 'realtype' -> 'othertype':
     assertOpenApiBackwardIncompatible(OPENAPI_DOC6, OPENAPI_DOC7);
   }
+
+  @Test
+  public void testOneOfDiscrimitatorMissingSameOrder() {
+    assertOpenApiAreEquals(OPENAPI_DOC8, OPENAPI_DOC8);
+  }
+
+  @Test
+  public void testOneOfDiscrimitatorMissingDifferentOrder() {
+    assertOpenApiAreEquals(OPENAPI_DOC8, OPENAPI_DOC9);
+  }
 }

src/test/java/com/qdesrame/openapi/test/OpenApiDiffTest.java → core/src/test/java/com/qdesrame/openapi/test/OpenApiDiffTest.java

@@ -3,12 +3,12 @@
 import static com.qdesrame.openapi.test.TestUtils.assertOpenApiAreEquals;
 import static org.assertj.core.api.Assertions.assertThat;
 
-import com.qdesrame.openapi.diff.OpenApiCompare;
-import com.qdesrame.openapi.diff.model.ChangedOpenApi;
-import com.qdesrame.openapi.diff.model.ChangedOperation;
-import com.qdesrame.openapi.diff.model.Endpoint;
-import com.qdesrame.openapi.diff.output.HtmlRender;
-import com.qdesrame.openapi.diff.output.MarkdownRender;
+import com.qdesrame.openapi.diff.core.OpenApiCompare;
+import com.qdesrame.openapi.diff.core.model.ChangedOpenApi;
+import com.qdesrame.openapi.diff.core.model.ChangedOperation;
+import com.qdesrame.openapi.diff.core.model.Endpoint;
+import com.qdesrame.openapi.diff.core.output.HtmlRender;
+import com.qdesrame.openapi.diff.core.output.MarkdownRender;
 import java.io.FileWriter;
 import java.io.IOException;
 import java.util.List;

core/src/test/java/com/qdesrame/openapi/test/ResponseAddedContentSchemaTest.java

@@ -0,0 +1,47 @@
+package com.qdesrame.openapi.test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import com.qdesrame.openapi.diff.core.OpenApiCompare;
+import com.qdesrame.openapi.diff.core.model.ChangedOpenApi;
+import com.qdesrame.openapi.diff.core.model.ChangedResponse;
+import com.qdesrame.openapi.diff.core.output.ConsoleRender;
+import com.qdesrame.openapi.diff.core.output.HtmlRender;
+import com.qdesrame.openapi.diff.core.output.MarkdownRender;
+import io.swagger.v3.oas.models.media.Content;
+import java.util.Map;
+import org.junit.jupiter.api.Test;
+
+public class ResponseAddedContentSchemaTest {
+
+  private final String OPENAPI_DOC1 = "response_schema_added_1.yaml";
+  private final String OPENAPI_DOC2 = "response_schema_added_2.yaml";
+
+  @Test
+  public void testDiffDifferent() {
+    ChangedOpenApi changedOpenApi = OpenApiCompare.fromLocations(OPENAPI_DOC1, OPENAPI_DOC2);
+
+    assertThat(changedOpenApi.getNewEndpoints()).isEmpty();
+    assertThat(changedOpenApi.getMissingEndpoints()).isEmpty();
+    assertThat(changedOpenApi.getChangedOperations()).isNotEmpty();
+
+    Map<String, ChangedResponse> changedResponses =
+        changedOpenApi.getChangedOperations().get(0).getApiResponses().getChanged();
+    assertThat(changedResponses).containsKey("200");
+
+    ChangedResponse changedResponse = changedResponses.get("200");
+    Content oldContent = changedResponse.getOldApiResponse().getContent();
+    Content newContent = changedResponse.getNewApiResponse().getContent();
+    assertThat(oldContent.get("application/json").getSchema()).isNull();
+    assertThat(newContent.get("application/json").getSchema()).isNotNull();
+  }
+
+  @Test
+  public void testDiffCanBeRendered() {
+    ChangedOpenApi changedOpenApi = OpenApiCompare.fromLocations(OPENAPI_DOC1, OPENAPI_DOC2);
+
+    assertThat(new ConsoleRender().render(changedOpenApi)).isNotBlank();
+    assertThat(new HtmlRender().render(changedOpenApi)).isNotBlank();
+    assertThat(new MarkdownRender().render(changedOpenApi)).isNotBlank();
+  }
+}

src/test/java/com/qdesrame/openapi/test/ResponseHeaderDiffTest.java → core/src/test/java/com/qdesrame/openapi/test/ResponseHeaderDiffTest.java

@@ -2,10 +2,10 @@
 
 import static org.assertj.core.api.Assertions.assertThat;
 
-import com.qdesrame.openapi.diff.OpenApiCompare;
-import com.qdesrame.openapi.diff.model.ChangedHeaders;
-import com.qdesrame.openapi.diff.model.ChangedOpenApi;
-import com.qdesrame.openapi.diff.model.ChangedResponse;
+import com.qdesrame.openapi.diff.core.OpenApiCompare;
+import com.qdesrame.openapi.diff.core.model.ChangedHeaders;
+import com.qdesrame.openapi.diff.core.model.ChangedOpenApi;
+import com.qdesrame.openapi.diff.core.model.ChangedResponse;
 import java.util.Map;
 import org.junit.jupiter.api.Test;
 

src/test/java/com/qdesrame/openapi/test/SecurityDiffTest.java → core/src/test/java/com/qdesrame/openapi/test/SecurityDiffTest.java

@@ -3,8 +3,8 @@
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
-import com.qdesrame.openapi.diff.OpenApiCompare;
-import com.qdesrame.openapi.diff.model.*;
+import com.qdesrame.openapi.diff.core.OpenApiCompare;
+import com.qdesrame.openapi.diff.core.model.*;
 import io.swagger.v3.oas.models.security.SecurityRequirement;
 import org.junit.jupiter.api.Test;
 
@@ -21,9 +21,7 @@ public void testDiffDifferent() {
     assertThat(changedOpenApi.getChangedOperations().size() == 3);
 
     ChangedOperation changedOperation1 =
-        changedOpenApi
-            .getChangedOperations()
-            .stream()
+        changedOpenApi.getChangedOperations().stream()
             .filter(x -> x.getPathUrl().equals("/pet/{petId}"))
             .findFirst()
             .get();
@@ -51,9 +49,7 @@ public void testDiffDifferent() {
                     .isEqualTo("read:pets"));
 
     ChangedOperation changedOperation2 =
-        changedOpenApi
-            .getChangedOperations()
-            .stream()
+        changedOpenApi.getChangedOperations().stream()
             .filter(x -> x.getPathUrl().equals("/pet3"))
             .findFirst()
             .get();
@@ -73,9 +69,7 @@ public void testDiffDifferent() {
     assertThat(changedImplicitOAuthFlow2.isAuthorizationUrl()).isTrue();
 
     ChangedOperation changedOperation3 =
-        changedOpenApi
-            .getChangedOperations()
-            .stream()
+        changedOpenApi.getChangedOperations().stream()
             .filter(x -> x.getPathUrl().equals("/pet/findByStatus2"))
             .findFirst()
             .get();

core/src/test/java/com/qdesrame/openapi/test/Swagger2CompatibilityTest.java

@@ -0,0 +1,22 @@
+package com.qdesrame.openapi.test;
+
+import static com.qdesrame.openapi.test.TestUtils.assertOpenApiAreEquals;
+
+import org.junit.jupiter.api.Disabled;
+import org.junit.jupiter.api.Test;
+
+@Disabled
+public class Swagger2CompatibilityTest {
+  private final String SWAGGER_DOC1 = "petstore_swagger2.yaml";
+  private final String OPENAPI_DOC2 = "petstore_openapi3.yaml";
+
+  @Test
+  public void testEqual() {
+    assertOpenApiAreEquals(SWAGGER_DOC1, SWAGGER_DOC1);
+  }
+
+  @Test
+  public void testSwagger2ToOpenapi3() {
+    assertOpenApiAreEquals(SWAGGER_DOC1, OPENAPI_DOC2);
+  }
+}

src/test/java/com/qdesrame/openapi/test/TestUtils.java → core/src/test/java/com/qdesrame/openapi/test/TestUtils.java

@@ -3,8 +3,8 @@
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.slf4j.LoggerFactory.getLogger;
 
-import com.qdesrame.openapi.diff.OpenApiCompare;
-import com.qdesrame.openapi.diff.model.ChangedOpenApi;
+import com.qdesrame.openapi.diff.core.OpenApiCompare;
+import com.qdesrame.openapi.diff.core.model.ChangedOpenApi;
 import org.slf4j.Logger;
 
 public class TestUtils {

core/src/test/resources/add-prop-put-1.yaml

@@ -0,0 +1,71 @@
+openapi: 3.0.0
+servers:
+  - description: SwaggerHub API Auto Mocking
+    url: https://virtserver.swaggerhub.com/anshul10s/pet-store/1.0.0
+info:
+  description: |
+    This is a sample Petstore server.  You can find
+    out more about Swagger at
+    [http://swagger.io](http://swagger.io) or on
+    [irc.freenode.net, #swagger](http://swagger.io/irc/).
+  version: "1.0.0"
+  title: Swagger Petstore
+  termsOfService: 'http://swagger.io/terms/'
+  contact:
+    email: apiteam@swagger.io
+  license:
+    name: Apache 2.0
+    url: 'http://www.apache.org/licenses/LICENSE-2.0.html'
+tags:
+  - name: pet
+    description: Everything about your Pets
+    externalDocs:
+      description: Find out more
+      url: 'http://swagger.io'
+  - name: store
+    description: Access to Petstore orders
+  - name: user
+    description: Operations about user
+    externalDocs:
+      description: Find out more about our store
+      url: 'http://swagger.io'
+paths:
+  /store/inventory/{id}:
+    put:
+      tags:
+        - store
+      summary: Updates the inventory with the given id
+      description: Updates the inventory with the given id and returns it
+      operationId: putInventory
+      parameters:
+        - name: id
+          in: path
+          description: Unique Id of the inventory
+          required: true
+          example: a-b-c-d
+          schema:
+            type: string
+      requestBody:
+        content:
+          application/json:
+            schema:
+              $ref: '#/components/schemas/Inventory'
+      responses:
+        '200':
+          description: successful operation
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Inventory'
+externalDocs:
+  description: Find out more about Swagger
+  url: 'http://swagger.io'
+components:
+  schemas:
+    Inventory:
+      type: object
+      properties:
+        id:
+          type: string
+        details:
+          type: count

core/src/test/resources/add-prop-put-2.yaml

@@ -0,0 +1,73 @@
+openapi: 3.0.0
+servers:
+  - description: SwaggerHub API Auto Mocking
+    url: https://virtserver.swaggerhub.com/anshul10s/pet-store/1.0.0
+info:
+  description: |
+    This is a sample Petstore server.  You can find
+    out more about Swagger at
+    [http://swagger.io](http://swagger.io) or on
+    [irc.freenode.net, #swagger](http://swagger.io/irc/).
+  version: "1.0.0"
+  title: Swagger Petstore
+  termsOfService: 'http://swagger.io/terms/'
+  contact:
+    email: apiteam@swagger.io
+  license:
+    name: Apache 2.0
+    url: 'http://www.apache.org/licenses/LICENSE-2.0.html'
+tags:
+  - name: pet
+    description: Everything about your Pets
+    externalDocs:
+      description: Find out more
+      url: 'http://swagger.io'
+  - name: store
+    description: Access to Petstore orders
+  - name: user
+    description: Operations about user
+    externalDocs:
+      description: Find out more about our store
+      url: 'http://swagger.io'
+paths:
+  /store/inventory/{id}:
+    put:
+      tags:
+        - store
+      summary: Updates the inventory with the given id
+      description: Updates the inventory with the given id and returns it
+      operationId: putInventory
+      parameters:
+        - name: id
+          in: path
+          description: Unique Id of the inventory
+          required: true
+          example: a-b-c-d
+          schema:
+            type: string
+      requestBody:
+        content:
+          application/json:
+            schema:
+              $ref: '#/components/schemas/Inventory'
+      responses:
+        '200':
+          description: successful operation
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Inventory'
+externalDocs:
+  description: Find out more about Swagger
+  url: 'http://swagger.io'
+components:
+  schemas:
+    Inventory:
+      type: object
+      properties:
+        id:
+          type: string
+        details:
+          type: count
+        extra_info:
+          type: string

src/test/resources/backwardCompatibility/bc_2.yaml → core/src/test/resources/backwardCompatibility/bc_2.yaml

@@ -36,9 +36,6 @@ paths:
       summary: Add a new pet to the store
       description: ''
       operationId: addPet
-      responses:
-        '405':
-          description: Invalid input
       requestBody:
         $ref: '#/components/requestBodies/Pet'
       responses:
@@ -48,6 +45,8 @@ paths:
             application/json:
               schema:
                 $ref: '#/components/schemas/MyResponseType'
+        '405':
+          description: Invalid input
   /pet/findByStatus:
     get:
       tags:

src/test/resources/backwardCompatibility/bc_3.yaml → core/src/test/resources/backwardCompatibility/bc_3.yaml

@@ -36,9 +36,6 @@ paths:
       summary: Add a new pet to the store
       description: ''
       operationId: addPet
-      responses:
-        '405':
-          description: Invalid input
       requestBody:
         $ref: '#/components/requestBodies/Pet'
       responses:
@@ -48,6 +45,8 @@ paths:
             application/json:
               schema:
                 $ref: '#/components/schemas/MyResponseType'
+        '405':
+          description: Invalid input
     get:
       tags:
         - pet

src/test/resources/backwardCompatibility/bc_4.yaml → core/src/test/resources/backwardCompatibility/bc_4.yaml

@@ -36,9 +36,6 @@ paths:
       summary: Add a new pet to the store
       description: ''
       operationId: addPet
-      responses:
-        '405':
-          description: Invalid input
       requestBody:
         $ref: '#/components/requestBodies/Pet'
       responses:
@@ -48,6 +45,8 @@ paths:
             application/json:
               schema:
                 $ref: '#/components/schemas/MyResponseType'
+        '405':
+          description: Invalid input
   /pet/findByStatus:
     get:
       tags:

core/src/test/resources/missing_property_1.yaml

@@ -0,0 +1,31 @@
+openapi: 3.0.1
+info:
+  title: Title
+  version: 1.0.0
+  description: Description
+paths:
+  /:
+    get:
+      summary: Simple GET
+      operationId: simpleGet
+      responses:
+        default:
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Wrapper'
+      description: Simple GET
+components:
+  schemas:
+    Wrapper:
+      type: object
+      properties:
+        id:
+          type: string
+        childProperty:
+          $ref: '#/components/schemas/ChildProperty'
+    ChildProperty:
+      type: object
+      properties:
+        id:
+          type: string

core/src/test/resources/missing_property_2.yaml

@@ -0,0 +1,24 @@
+openapi: 3.0.1
+info:
+  title: Title
+  version: 1.0.0
+  description: Description
+paths:
+  /:
+    get:
+      summary: Simple GET
+      operationId: simpleGet
+      responses:
+        default:
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Wrapper'
+      description: Simple GET
+components:
+  schemas:
+    Wrapper:
+      type: object
+      properties:
+        id:
+          type: string

core/src/test/resources/oneOf_discriminator-missing_1.yaml

@@ -0,0 +1,44 @@
+openapi: 3.0.1
+info:
+  title: oneOf test for issue 29
+  version: '1.0'
+servers:
+  - url: 'http://localhost:8000/'
+paths:
+  /state:
+    post:
+      operationId: update
+      requestBody:
+        content:
+            application/json:
+              schema:
+                oneOf:
+                  - $ref: '#/components/schemas/A'
+                  - $ref: '#/components/schemas/B'
+        required: true
+      responses:
+        '201':
+          description: OK
+components:
+  schemas:
+    A:
+      type: object
+      properties:
+        realtype:
+          type: string
+        othertype:
+          type: string
+        message:
+          type: string
+    B:
+      type: object
+      properties:
+        realtype:
+          type: string
+        othertype:
+          type: string
+        description:
+          type: string
+        code:
+          type: integer
+          format: int32 

core/src/test/resources/oneOf_discriminator-missing_2.yaml

@@ -0,0 +1,44 @@
+openapi: 3.0.1
+info:
+  title: oneOf test for issue 29
+  version: '1.0'
+servers:
+  - url: 'http://localhost:8000/'
+paths:
+  /state:
+    post:
+      operationId: update
+      requestBody:
+        content:
+            application/json:
+              schema:
+                oneOf:
+                  - $ref: '#/components/schemas/B'
+                  - $ref: '#/components/schemas/A'
+        required: true
+      responses:
+        '201':
+          description: OK
+components:
+  schemas:
+    A:
+      type: object
+      properties:
+        realtype:
+          type: string
+        othertype:
+          type: string
+        message:
+          type: string
+    B:
+      type: object
+      properties:
+        realtype:
+          type: string
+        othertype:
+          type: string
+        description:
+          type: string
+        code:
+          type: integer
+          format: int32

core/src/test/resources/petstore_openapi3.yaml

@@ -0,0 +1,109 @@
+openapi: "3.0.0"
+info:
+  version: 1.0.0
+  title: Swagger Petstore
+  license:
+    name: MIT
+servers:
+  - url: http://petstore.swagger.io/v1
+paths:
+  /pets:
+    get:
+      summary: List all pets
+      operationId: listPets
+      tags:
+        - pets
+      parameters:
+        - name: limit
+          in: query
+          description: How many items to return at one time (max 100)
+          required: false
+          schema:
+            type: integer
+            format: int32
+      responses:
+        '200':
+          description: A paged array of pets
+          headers:
+            x-next:
+              description: A link to the next page of responses
+              schema:
+                type: string
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Pets"
+        default:
+          description: unexpected error
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Error"
+    post:
+      summary: Create a pet
+      operationId: createPets
+      tags:
+        - pets
+      responses:
+        '201':
+          description: Null response
+        default:
+          description: unexpected error
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Error"
+  /pets/{petId}:
+    get:
+      summary: Info for a specific pet
+      operationId: showPetById
+      tags:
+        - pets
+      parameters:
+        - name: petId
+          in: path
+          required: true
+          description: The id of the pet to retrieve
+          schema:
+            type: string
+      responses:
+        '200':
+          description: Expected response to a valid request
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Pets"
+        default:
+          description: unexpected error
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Error"
+components:
+  schemas:
+    Pet:
+      required:
+        - id
+        - name
+      properties:
+        id:
+          type: integer
+          format: int64
+        name:
+          type: string
+        tag:
+          type: string
+    Pets:
+      type: array
+      items:
+        $ref: "#/components/schemas/Pet"
+    Error:
+      required:
+        - code
+        - message
+      properties:
+        code:
+          type: integer
+          format: int32
+        message:
+          type: string

core/src/test/resources/petstore_swagger2.yaml

@@ -0,0 +1,101 @@
+swagger: "2.0"
+info:
+  version: 1.0.0
+  title: Swagger Petstore
+  license:
+    name: MIT
+host: petstore.swagger.io
+basePath: /v1
+schemes:
+  - http
+consumes:
+  - application/json
+produces:
+  - application/json
+paths:
+  /pets:
+    get:
+      summary: List all pets
+      operationId: listPets
+      tags:
+        - pets
+      parameters:
+        - name: limit
+          in: query
+          description: How many items to return at one time (max 100)
+          required: false
+          type: integer
+          format: int32
+      responses:
+        "200":
+          description: A paged array of pets
+          headers:
+            x-next:
+              type: string
+              description: A link to the next page of responses
+          schema:
+            $ref: '#/definitions/Pets'
+        default:
+          description: unexpected error
+          schema:
+            $ref: '#/definitions/Error'
+    post:
+      summary: Create a pet
+      operationId: createPets
+      tags:
+        - pets
+      responses:
+        "201":
+          description: Null response
+        default:
+          description: unexpected error
+          schema:
+            $ref: '#/definitions/Error'
+  /pets/{petId}:
+    get:
+      summary: Info for a specific pet
+      operationId: showPetById
+      tags:
+        - pets
+      parameters:
+        - name: petId
+          in: path
+          required: true
+          description: The id of the pet to retrieve
+          type: string
+      responses:
+        "200":
+          description: Expected response to a valid request
+          schema:
+            $ref: '#/definitions/Pets'
+        default:
+          description: unexpected error
+          schema:
+            $ref: '#/definitions/Error'
+definitions:
+  Pet:
+    required:
+      - id
+      - name
+    properties:
+      id:
+        type: integer
+        format: int64
+      name:
+        type: string
+      tag:
+        type: string
+  Pets:
+    type: array
+    items:
+      $ref: '#/definitions/Pet'
+  Error:
+    required:
+      - code
+      - message
+    properties:
+      code:
+        type: integer
+        format: int32
+      message:
+        type: string

core/src/test/resources/response_schema_added_1.yaml

@@ -0,0 +1,106 @@
+openapi: "3.0.0"
+info:
+  version: 1.0.0
+  title: Swagger Petstore
+  license:
+    name: MIT
+servers:
+  - url: http://petstore.swagger.io/v1
+paths:
+  /pets:
+    get:
+      summary: List all pets
+      operationId: listPets
+      tags:
+        - pets
+      parameters:
+        - name: limit
+          in: query
+          description: How many items to return at one time (max 100)
+          required: false
+          schema:
+            type: integer
+            format: int32
+      responses:
+        '200':
+          description: A paged array of pets
+          headers:
+            x-next:
+              description: A link to the next page of responses
+              schema:
+                type: string
+          content:
+            application/json: {}
+        default:
+          description: unexpected error
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Error"
+    post:
+      summary: Create a pet
+      operationId: createPets
+      tags:
+        - pets
+      responses:
+        '201':
+          description: Null response
+        default:
+          description: unexpected error
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Error"
+  /pets/{petId}:
+    get:
+      summary: Info for a specific pet
+      operationId: showPetById
+      tags:
+        - pets
+      parameters:
+        - name: petId
+          in: path
+          required: true
+          description: The id of the pet to retrieve
+          schema:
+            type: string
+      responses:
+        '200':
+          description: Expected response to a valid request
+          content:
+            application/json:
+                $ref: "#/components/schemas/Pets"
+        default:
+          description: unexpected error
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Error"
+components:
+  schemas:
+    Pet:
+      required:
+        - id
+        - name
+      properties:
+        id:
+          type: integer
+          format: int64
+        name:
+          type: string
+        tag:
+          type: string
+    Pets:
+      type: array
+      items:
+        $ref: "#/components/schemas/Pet"
+    Error:
+      required:
+        - code
+        - message
+      properties:
+        code:
+          type: integer
+          format: int32
+        message:
+          type: string