Add flaky test attribute

.vscode/settings.json

@@ -12,5 +12,6 @@
   "[json]": {
     "editor.tabSize": 2
   },
+  "dotnet.defaultSolution": "Razor.sln",
   "omnisharp.defaultLaunchSolution": "Razor.sln"
 }

azure-pipelines-integration-dartlab.yml

@@ -29,6 +29,8 @@ variables:
   value: $(Build.SourcesDirectory)\artifacts\log\$(_configuration)
 - name: __VSNeverShowWhatsNew
   value: 1
+- name: RAZOR_RUN_FLAKY_TESTS
+  value: 'true'
 
 stages:
 - template: \stages\visual-studio\agent.yml@DartLabTemplates

src/Razor/test/Microsoft.VisualStudio.Razor.IntegrationTests/DiagnosticTests.cs

@@ -8,7 +8,7 @@ namespace Microsoft.VisualStudio.Razor.IntegrationTests;
 
 public class DiagnosticTests : AbstractRazorEditorTest
 {
-    [IdeFact(Skip = "https://github.com/dotnet/razor/issues/8150")]
+    [FlakyFact(Issue = "https://github.com/dotnet/razor/issues/8150")]
     public async Task Diagnostics_ShowErrors_Razor()
     {
         // Arrange
@@ -48,7 +48,7 @@ public void Function(){
             });
     }
 
-    [IdeFact(Skip = "https://github.com/dotnet/razor/issues/8150")]
+    [FlakyFact(Issue = "https://github.com/dotnet/razor/issues/8150")]
     public async Task Diagnostics_ShowErrors_Html()
     {
         // Arrange
@@ -80,7 +80,7 @@ await TestServices.Editor.SetTextAsync(@"
             });
     }
 
-    [IdeFact(Skip = "https://github.com/dotnet/razor/issues/8150")]
+    [FlakyFact(Issue = "https://github.com/dotnet/razor/issues/8150")]
     public async Task Diagnostics_ShowErrors_CSharp()
     {
         // Arrange
@@ -112,7 +112,7 @@ await TestServices.Editor.SetTextAsync(@"
             });
     }
 
-    [IdeFact(Skip = "https://github.com/dotnet/razor/issues/8150")]
+    [FlakyFact(Issue = "https://github.com/dotnet/razor/issues/8150")]
     public async Task Diagnostics_ShowErrors_CSharp_NoDocType()
     {
         // Why this test, when we have the above test, and they seem so similar, and we also have Diagnostics_ShowErrors_CSharpAndHtml you ask? Well I'll tell you!
@@ -152,7 +152,7 @@ await TestServices.Editor.SetTextAsync(@"
             });
     }
 
-    [IdeFact(Skip = "https://github.com/dotnet/razor/issues/8150")]
+    [FlakyFact(Issue = "https://github.com/dotnet/razor/issues/8150")]
     public async Task Diagnostics_ShowErrors_CSharpAndHtml()
     {
         // Arrange

src/Razor/test/Microsoft.VisualStudio.Razor.IntegrationTests/FlakyFactAttribute.cs

@@ -0,0 +1,41 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT license. See License.txt in the project root for license information.
+
+using System;
+using Xunit;
+
+namespace Microsoft.VisualStudio.Razor.IntegrationTests;
+
+[AttributeUsage(AttributeTargets.Method, AllowMultiple = false)]
+public class FlakyFactAttribute : IdeFactAttribute
+{
+    private readonly Lazy<bool> _runFlakyTests = new(() => Environment.GetEnvironmentVariable("RAZOR_RUN_FLAKY_TESTS")?.ToLower() == "true");
+
+    public FlakyFactAttribute()
+    {
+    }
+
+    private string _issue = "";
+    public string Issue
+    {
+        get => _issue;
+        set
+        {
+            _issue = value;
+
+            if (!_runFlakyTests.Value)
+            {
+                #pragma warning disable CS0618
+                Skip = _issue;
+                #pragma warning restore CS0618
+            }
+        }
+    }
+
+    [Obsolete("Use Issue instead of Skip")]
+    public new string Skip
+    {
+        get => base.Skip;
+        set => base.Skip = value;
+    }
+}