Merge pull request #4848 from Arkatufus/Fix_APIApprover_NRE_bug

Fix Akka.API.Tests spec always throws NRE when failed in CI/CD pipeline

Author: IgorFedchenko

src/core/Akka.API.Tests/CoreAPISpec.cs

@@ -26,18 +26,21 @@
 using Akka.Persistence.Sql.Common.Journal;
 using ApprovalTests.Core;
 using ApprovalTests.Reporters;
+using ApprovalTests.Reporters.Mac;
+using ApprovalUtilities.Utilities;
 using DiffPlex;
 using DiffPlex.DiffBuilder;
 using DiffPlex.DiffBuilder.Model;
-using Xunit.Abstractions;
 using Xunit.Sdk;
+using P4MergeReporter = ApprovalTests.Reporters.P4MergeReporter;
+using P4MacMergeReporter = ApprovalTests.Reporters.Mac.P4MergeReporter;
 
 namespace Akka.API.Tests
 {
 #if(DEBUG)
-    [UseReporter(typeof(DiffPlexReporter), typeof(DiffReporter), typeof(AllFailingTestsClipboardReporter))]
+    [UseReporter(typeof(DiffPlexReporter), typeof(CustomDiffReporter), typeof(AllFailingTestsClipboardReporter))]
 #else
-    [UseReporter(typeof(DiffPlexReporter))]
+    [UseReporter(typeof(DiffPlexReporter), typeof(CustomDiffReporter))]
 #endif
     public class CoreAPISpec
     {
@@ -173,6 +176,64 @@ public ApiNotApprovedException(string message) : base($"Failed API approval. Dif
         public override string StackTrace { get; } = string.Empty;
     }
 
+    #region Suppress FrameworkAssertReporter hack
+    // The built-in FrameworkAssertReporter that is being called inside the DiffReporter class
+    // is buggy in a CI/CD environment because it is trying to be clever, could not distinguish
+    // between XUnit and XUnit2, and will throw Null Reference Exception every time it ran.
+    //
+    // This is probably fixed in latest version of ApiApprover but we couldn't switch to that
+    // version because the latest ApiGenerator returns a different API report format.
+    //
+    // FIX: This hack removes FrameworkAssertReporter from the possible reporter list and retains
+    // all of the other reporters in DiffReporter
+
+    internal class CustomDiffReporter : FirstWorkingReporter
+    {
+        public CustomDiffReporter() : base(
+            CustomWindowsDiffReporter.Instance, 
+            CustomMacDiffReporter.Instance)
+        { }
+    }
+
+    internal class CustomMacDiffReporter : FirstWorkingReporter
+    {
+        public static readonly CustomMacDiffReporter Instance = new CustomMacDiffReporter();
+        public CustomMacDiffReporter()
+            : base(
+
+                BeyondCompareMacReporter.INSTANCE,
+                DiffMergeReporter.INSTANCE,
+                KaleidoscopeDiffReporter.INSTANCE,
+                P4MacMergeReporter.INSTANCE,
+                KDiff3Reporter.INSTANCE,
+                TkDiffReporter.INSTANCE,
+                QuietReporter.INSTANCE)
+        { }
+
+        public override bool IsWorkingInThisEnvironment(string forFile) => OsUtils.IsUnixOs() && base.IsWorkingInThisEnvironment(forFile);
+    }
+
+    internal class CustomWindowsDiffReporter : FirstWorkingReporter
+    {
+        public static readonly CustomWindowsDiffReporter Instance = new CustomWindowsDiffReporter();
+        public CustomWindowsDiffReporter()
+            : base(
+                CodeCompareReporter.INSTANCE,
+                BeyondCompareReporter.INSTANCE,
+                TortoiseDiffReporter.INSTANCE,
+                AraxisMergeReporter.INSTANCE,
+                P4MergeReporter.INSTANCE,
+                WinMergeReporter.INSTANCE,
+                KDiffReporter.INSTANCE,
+                VisualStudioReporter.INSTANCE,
+                QuietReporter.INSTANCE)
+        { }
+
+        public override bool IsWorkingInThisEnvironment(string forFile) => OsUtils.IsWindowsOs() && base.IsWorkingInThisEnvironment(forFile);
+    }
+
+    #endregion
+
     internal class DiffPlexReporter : IApprovalFailureReporter
     {
         public void Report(string approved, string received)