set correct stack trace for async rejections of non-errors (jestjs#6230)

Author: SimenB

integration-tests/__tests__/__snapshots__/failures.test.js.snap

@@ -130,6 +130,7 @@ exports[`not throwing Error objects 5`] = `
   ✕ Error during test
   ✕ done(Error)
   ✕ done(non-error)
+  ✕ returned promise rejection
 
   ● Promise thrown during test
 
@@ -243,10 +244,33 @@ exports[`not throwing Error objects 5`] = `
          |   ^
       37 | });
       38 | 
+      39 | test('returned promise rejection', () => {
 
-      at packages/jest-jasmine2/build/jasmine/Env.js:541:34
+      at packages/jest-jasmine2/build/jasmine/Env.js:537:34
       at __tests__/during_tests.test.js:36:3
 
+  ● returned promise rejection
+
+    Failed: Object {
+      \\"notAnError\\": Array [
+        Object {
+          \\"hello\\": true,
+          \\"tooDeep\\": [Object],
+        },
+      ],
+    }
+
+      37 | });
+      38 | 
+    > 39 | test('returned promise rejection', () => {
+         | ^
+      40 |   return Promise.reject(deepObject);
+      41 | });
+      42 | 
+
+      at packages/jest-jasmine2/build/jasmine_async.js:102:24
+      at __tests__/during_tests.test.js:39:1
+
 "
 `;
 

integration-tests/failures/__tests__/during_tests.test.js

@@ -35,3 +35,7 @@ test('done(Error)', done => {
 test('done(non-error)', done => {
   done(deepObject);
 });
+
+test('returned promise rejection', () => {
+  return Promise.reject(deepObject);
+});

jest

@@ -7,4 +7,6 @@ This source code is licensed under the MIT license found in the
 LICENSE file in the root directory of this source tree.
 '
 
-node ./packages/jest-cli/bin/jest "$@"
+DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+
+node "$DIR"/packages/jest-cli/bin/jest "$@"

packages/jest-jasmine2/src/is_error.js

@@ -0,0 +1,23 @@
+/**
+ * Copyright (c) 2014-present, Facebook, Inc. All rights reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ */
+
+import prettyFormat from 'pretty-format';
+
+export default function isError(potentialError: any) {
+  // duck-type Error, see #2549
+  const isError =
+    typeof potentialError === 'object' &&
+    typeof potentialError.message === 'string' &&
+    typeof potentialError.name === 'string';
+  const message = isError
+    ? null
+    : `Failed: ${prettyFormat(potentialError, {maxDepth: 3})}`;
+
+  return {isError, message};
+}

packages/jest-jasmine2/src/jasmine/Env.js

@@ -32,7 +32,7 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 import queueRunner from '../queue_runner';
 import treeProcessor from '../tree_processor';
-import prettyFormat from 'pretty-format';
+import checkIsError from '../is_error';
 
 // Try getting the real promise object from the context, if available. Someone
 // could have overridden it in a test. Async functions return it implicitly.
@@ -547,12 +547,7 @@ export default function(j$) {
     };
 
     this.fail = function(error) {
-      // duck-type Error, see #2549
-      const isError =
-        typeof error === 'object' &&
-        typeof error.message === 'string' &&
-        typeof error.name === 'string';
-      const message = `Failed: ${prettyFormat(error, {maxDepth: 3})}`;
+      const {isError, message} = checkIsError(error);
 
       currentRunnable().addExpectationResult(false, {
         matcherName: '',

packages/jest-jasmine2/src/jasmine_async.js

@@ -16,6 +16,7 @@ import type {Global} from 'types/Global';
 
 import isGeneratorFn from 'is-generator-fn';
 import co from 'co';
+import checkIsError from './is_error';
 
 function isPromise(obj) {
   return obj && typeof obj.then === 'function';
@@ -34,14 +35,23 @@ function promisifyLifeCycleFunction(originalFn, env) {
       return originalFn.call(env, fn, timeout);
     }
 
+    const extraError = new Error();
+
     // We make *all* functions async and run `done` right away if they
     // didn't return a promise.
     const asyncFn = function(done) {
       const wrappedFn = isGeneratorFn(fn) ? co.wrap(fn) : fn;
       const returnValue = wrappedFn.call({});
 
       if (isPromise(returnValue)) {
-        returnValue.then(done.bind(null, null), done.fail);
+        returnValue.then(done.bind(null, null), error => {
+          const {isError, message} = checkIsError(error);
+
+          if (message) {
+            extraError.message = message;
+          }
+          done.fail(isError ? error : extraError);
+        });
       } else {
         done();
       }
@@ -67,12 +77,21 @@ function promisifyIt(originalFn, env) {
       return originalFn.call(env, specName, fn, timeout);
     }
 
+    const extraError = new Error();
+
     const asyncFn = function(done) {
       const wrappedFn = isGeneratorFn(fn) ? co.wrap(fn) : fn;
       const returnValue = wrappedFn.call({});
 
       if (isPromise(returnValue)) {
-        returnValue.then(done.bind(null, null), done.fail);
+        returnValue.then(done.bind(null, null), error => {
+          const {isError, message} = checkIsError(error);
+
+          if (message) {
+            extraError.message = message;
+          }
+          done.fail(isError ? error : extraError);
+        });
       } else if (returnValue === undefined) {
         done();
       } else {