leverage DoesNotReturnIfAttribute for better assertion (#3168)

Author: SimonCropp

test/UnitTests/MSTestAdapter.UnitTests/Execution/TestMethodInfoTests.cs

@@ -299,9 +299,10 @@ public void TestMethodInfoInvokeShouldSetStackTraceInformationIfTestClassConstru
         var exception = _testMethodInfo.Invoke(null).TestFailureException as TestFailedException;
 
         Verify(exception is not null);
+        Verify(exception.StackTraceInformation is not null);
         Verify(
-            (bool)exception?.StackTraceInformation.ErrorStackTrace.StartsWith(
-            "    at Microsoft.VisualStudio.TestPlatform.MSTestAdapter.UnitTests.Execution.TestMethodInfoTests.<>c.<TestMethodInfoInvokeShouldSetStackTraceInformationIfTestClassConstructorThrows>b__", StringComparison.Ordinal));
+            exception.StackTraceInformation.ErrorStackTrace.StartsWith(
+                "    at Microsoft.VisualStudio.TestPlatform.MSTestAdapter.UnitTests.Execution.TestMethodInfoTests.<>c.<TestMethodInfoInvokeShouldSetStackTraceInformationIfTestClassConstructorThrows>b__", StringComparison.Ordinal));
     }
 
     public void TestMethodInfoInvokeShouldSetStackTraceInformationIfTestClassConstructorThrowsWithoutInnerException()
@@ -313,8 +314,9 @@ public void TestMethodInfoInvokeShouldSetStackTraceInformationIfTestClassConstru
         var exception = method.Invoke(null).TestFailureException as TestFailedException;
 
         Verify(exception is not null);
+        Verify(exception.StackTraceInformation is not null);
         Verify(
-            (bool)exception?.StackTraceInformation.ErrorStackTrace.StartsWith(
+            exception.StackTraceInformation.ErrorStackTrace.StartsWith(
             "    at System.Reflection.RuntimeConstructorInfo.Invoke(BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)", StringComparison.Ordinal));
     }
 
@@ -403,9 +405,10 @@ public void TestMethodInfoInvokeShouldSetStackTraceInformationIfSetTestContextTh
         var exception = _testMethodInfo.Invoke(null).TestFailureException as TestFailedException;
 
         Verify(exception is not null);
+        Verify(exception.StackTraceInformation is not null);
         Verify(
-            (bool)exception?.StackTraceInformation.ErrorStackTrace.StartsWith(
-            "    at Microsoft.VisualStudio.TestPlatform.MSTestAdapter.UnitTests.Execution.TestMethodInfoTests.<>c.<TestMethodInfoInvokeShouldSetStackTraceInformationIfSetTestContextThrows>b__", StringComparison.Ordinal));
+            exception.StackTraceInformation.ErrorStackTrace.StartsWith(
+                "    at Microsoft.VisualStudio.TestPlatform.MSTestAdapter.UnitTests.Execution.TestMethodInfoTests.<>c.<TestMethodInfoInvokeShouldSetStackTraceInformationIfSetTestContextThrows>b__", StringComparison.Ordinal));
     }
 
     #endregion

test/Utilities/TestFramework.ForTestingMSTest/DoesNotReturnIfAttribute.cs

@@ -0,0 +1,39 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+#if NETSTANDARD2_0 || NETFRAMEWORK
+
+#pragma warning disable SA1623 // Remove ridiculous stylecop documentation warning
+namespace System.Diagnostics.CodeAnalysis;
+
+/// <summary>
+///   Specifies that the method will not return if the associated <see cref="bool"/>
+///   parameter is passed the specified value.
+/// </summary>
+[ExcludeFromCodeCoverage]
+[DebuggerNonUserCode]
+[AttributeUsage(AttributeTargets.Parameter)]
+public sealed class DoesNotReturnIfAttribute :
+    Attribute
+{
+    /// <summary>
+    ///   Gets the condition parameter value.
+    ///   Code after the method is considered unreachable by diagnostics if the argument
+    ///   to the associated parameter matches this value.
+    /// </summary>
+    public bool ParameterValue { get; }
+
+    /// <summary>
+    ///   Initializes a new instance of the <see cref="DoesNotReturnIfAttribute"/>
+    ///   class with the specified parameter value.
+    /// </summary>
+    /// <param name="parameterValue">
+    ///   The condition parameter value.
+    ///   Code after the method is considered unreachable by diagnostics if the argument
+    ///   to the associated parameter matches this value.
+    /// </param>
+    public DoesNotReturnIfAttribute(bool parameterValue) =>
+        ParameterValue = parameterValue;
+}
+
+#endif

test/Utilities/TestFramework.ForTestingMSTest/TestContainer.cs

@@ -51,7 +51,7 @@ public void Dispose()
     }
 
     public static void Verify(
-        bool condition,
+        [DoesNotReturnIf(false)] bool condition,
         [CallerArgumentExpression(nameof(condition))] string? expression = default,
         [CallerMemberName] string? caller = default,
         [CallerFilePath] string? filePath = default,