Update lightup and tests for Diagnostic.IsSuppressed

src/Microsoft.CodeAnalysis.Testing/Microsoft.CodeAnalysis.Analyzer.Testing/AnalyzerTest`1.cs

@@ -412,15 +412,8 @@ namespace Microsoft.CodeAnalysis.Testing
 
                 if (expected.IsSuppressed.HasValue)
                 {
-                    if (actual.diagnostic.TryGetIsSuppressed(out var actualValue))
-                    {
-                        message = FormatVerifierMessage(analyzers, actual.diagnostic, expected, $"Expected diagnostic suppression state to match");
-                        verifier.Equal(expected.IsSuppressed.Value, actualValue, message);
-                    }
-                    else
-                    {
-                        throw new NotSupportedException("DiagnosticSuppressors are not supported on this platform.");
-                    }
+                    message = FormatVerifierMessage(analyzers, actual.diagnostic, expected, $"Expected diagnostic suppression state to match");
+                    verifier.Equal(expected.IsSuppressed.Value, actual.diagnostic.IsSuppressed(), message);
                 }
 
                 DiagnosticVerifier?.Invoke(actual.diagnostic, expected, verifier);
@@ -817,11 +810,9 @@ namespace Microsoft.CodeAnalysis.Testing
                     builder.Append(")");
                 }
 
-                if (diagnostics[i].TryGetIsSuppressed(out var isSuppressed) && isSuppressed)
+                if (diagnostics[i].IsSuppressed())
                 {
-                    builder.Append($".{nameof(DiagnosticResult.WithIsSuppressed)}(");
-                    builder.Append(isSuppressed);
-                    builder.Append(")");
+                    builder.Append($".{nameof(DiagnosticResult.WithIsSuppressed)}(true)");
                 }
 
                 builder.AppendLine(",");
@@ -910,7 +901,7 @@ namespace Microsoft.CodeAnalysis.Testing
                 if (diagnostics[i].IsSuppressed.HasValue)
                 {
                     builder.Append($".{nameof(DiagnosticResult.WithIsSuppressed)}(");
-                    builder.Append(diagnostics[i].IsSuppressed.GetValueOrDefault());
+                    builder.Append(diagnostics[i].IsSuppressed.GetValueOrDefault() ? "true" : "false");
                     builder.Append(")");
                 }
 

src/Microsoft.CodeAnalysis.Testing/Microsoft.CodeAnalysis.Analyzer.Testing/Extensions/DiagnosticExtensions.cs

@@ -3,30 +3,28 @@
 // See the LICENSE file in the project root for more information.
 
 using System;
-using System.Collections.Generic;
 using System.Reflection;
-using System.Text;
 
 namespace Microsoft.CodeAnalysis.Testing.Extensions
 {
     internal static class DiagnosticExtensions
     {
-        private static readonly MethodInfo? IsSuppressedGetMethod = typeof(Diagnostic).GetProperty("IsSuppressed")?.GetMethod;
+        private static readonly Func<Diagnostic, bool> s_isSuppressed;
 
-        public static bool TryGetIsSuppressed(this Diagnostic diagnostic, out bool value)
+        static DiagnosticExtensions()
         {
-            value = false;
-
-            var rawValue = IsSuppressedGetMethod?.Invoke(diagnostic, null);
-
-            if (rawValue?.GetType() != typeof(bool))
+            var isSuppressedProperty = typeof(Diagnostic).GetProperty(nameof(IsSuppressed), typeof(bool));
+            if (isSuppressedProperty is { GetMethod: { } getMethod })
             {
-                return false;
+                s_isSuppressed = (Func<Diagnostic, bool>)getMethod.CreateDelegate(typeof(Func<Diagnostic, bool>), target: null);
+            }
+            else
+            {
+                s_isSuppressed = diagnostic => false;
             }
-
-            value = (bool)rawValue;
-
-            return true;
         }
+
+        public static bool IsSuppressed(this Diagnostic diagnostic)
+            => s_isSuppressed(diagnostic);
     }
 }

tests/Microsoft.CodeAnalysis.Testing/Microsoft.CodeAnalysis.Analyzer.Testing.UnitTests/DiagnosticSuppressorTests.cs

@@ -0,0 +1,140 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+#if !NETCOREAPP1_1 && !NET46
+
+using System;
+using System.Collections.Immutable;
+using System.Threading.Tasks;
+using Microsoft.CodeAnalysis.Diagnostics;
+using Microsoft.CodeAnalysis.Testing.TestAnalyzers;
+using Xunit;
+using CSharpAnalyzerTest = Microsoft.CodeAnalysis.Testing.TestAnalyzers.CSharpAnalyzerTest<
+    Microsoft.CodeAnalysis.Testing.TestAnalyzers.HighlightBracesAnalyzer>;
+using CSharpTest = Microsoft.CodeAnalysis.Testing.TestAnalyzers.CSharpSuppressorTest<
+    Microsoft.CodeAnalysis.Testing.TestAnalyzers.HighlightBracesAnalyzer,
+    Microsoft.CodeAnalysis.Testing.DiagnosticSuppressorTests.HighlightBracesSuppressor>;
+
+namespace Microsoft.CodeAnalysis.Testing
+{
+    public class DiagnosticSuppressorTests
+    {
+        private static readonly DiagnosticDescriptor DiagnosticDescriptor = new HighlightBracesAnalyzer().Descriptor;
+
+        [Fact]
+        public async Task TestUnspecifiedSuppression()
+        {
+            await new CSharpTest
+            {
+                TestState =
+                {
+                    Sources = { "namespace MyNamespace {|#0:{|} }" },
+                    ExpectedDiagnostics =
+                    {
+                        new DiagnosticResult(DiagnosticDescriptor).WithLocation(0).WithIsSuppressed(null),
+                    },
+                },
+            }.RunAsync();
+        }
+
+        [Fact]
+        public async Task TestNormalSuppression()
+        {
+            await new CSharpTest
+            {
+                TestState =
+                {
+                    Sources = { "namespace MyNamespace {|#0:{|} }" },
+                    ExpectedDiagnostics =
+                    {
+                        new DiagnosticResult(DiagnosticDescriptor).WithLocation(0).WithIsSuppressed(true),
+                    },
+                },
+            }.RunAsync();
+        }
+
+        [Fact]
+        public async Task TestUnexpectedSuppressionPresent()
+        {
+            var exception = await Assert.ThrowsAsync<InvalidOperationException>(async () =>
+            {
+                await new CSharpTest
+                {
+                    TestState =
+                    {
+                        Sources = { "namespace MyNamespace {|#0:{|} }" },
+                        ExpectedDiagnostics =
+                        {
+                            new DiagnosticResult(DiagnosticDescriptor).WithLocation(0).WithIsSuppressed(false),
+                        },
+                    },
+                }.RunAsync();
+            });
+
+            var expected =
+                "Expected diagnostic suppression state to match" + Environment.NewLine +
+                Environment.NewLine +
+                "Expected diagnostic:" + Environment.NewLine +
+                "    // /0/Test0.cs(1,23,1,24): warning Brace: message" + Environment.NewLine +
+                "VerifyCS.Diagnostic().WithSpan(1, 23, 1, 24).WithIsSuppressed(false)," + Environment.NewLine +
+                Environment.NewLine +
+                "Actual diagnostic:" + Environment.NewLine +
+                "    // /0/Test0.cs(1,23): warning Brace: message" + Environment.NewLine +
+                "VerifyCS.Diagnostic().WithSpan(1, 23, 1, 24).WithIsSuppressed(true)," + Environment.NewLine +
+                Environment.NewLine;
+            new DefaultVerifier().EqualOrDiff(expected, exception.Message);
+        }
+
+        [Fact]
+        public async Task TestExpectedSuppressionMissing()
+        {
+            var exception = await Assert.ThrowsAsync<InvalidOperationException>(async () =>
+            {
+                await new CSharpAnalyzerTest
+                {
+                    TestState =
+                    {
+                        Sources = { "namespace MyNamespace {|#0:{|} }" },
+                        ExpectedDiagnostics =
+                        {
+                            new DiagnosticResult(DiagnosticDescriptor).WithLocation(0).WithIsSuppressed(true),
+                        },
+                    },
+                }.RunAsync();
+            });
+
+            var expected =
+                "Expected diagnostic suppression state to match" + Environment.NewLine +
+                Environment.NewLine +
+                "Expected diagnostic:" + Environment.NewLine +
+                "    // /0/Test0.cs(1,23,1,24): warning Brace: message" + Environment.NewLine +
+                "VerifyCS.Diagnostic().WithSpan(1, 23, 1, 24).WithIsSuppressed(true)," + Environment.NewLine +
+                Environment.NewLine +
+                "Actual diagnostic:" + Environment.NewLine +
+                "    // /0/Test0.cs(1,23): warning Brace: message" + Environment.NewLine +
+                "VerifyCS.Diagnostic().WithSpan(1, 23, 1, 24)," + Environment.NewLine +
+                Environment.NewLine;
+            new DefaultVerifier().EqualOrDiff(expected, exception.Message);
+        }
+
+        [DiagnosticAnalyzer(LanguageNames.CSharp)]
+        internal class HighlightBracesSuppressor : DiagnosticSuppressor
+        {
+            internal static readonly SuppressionDescriptor Descriptor =
+                new SuppressionDescriptor("XBrace", DiagnosticDescriptor.Id, "justification");
+
+            public override ImmutableArray<SuppressionDescriptor> SupportedSuppressions => ImmutableArray.Create(Descriptor);
+
+            public override void ReportSuppressions(SuppressionAnalysisContext context)
+            {
+                foreach (var diagnostic in context.ReportedDiagnostics)
+                {
+                    context.ReportSuppression(Suppression.Create(Descriptor, diagnostic));
+                }
+            }
+        }
+    }
+}
+
+#endif

tests/Microsoft.CodeAnalysis.Testing/Microsoft.CodeAnalysis.Analyzer.Testing.UnitTests/TestAnalyzers/CSharpSuppressorTest`2.cs

@@ -0,0 +1,22 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+#if !NETCOREAPP1_1 && !NET46
+
+using System.Collections.Generic;
+using System.Linq;
+using Microsoft.CodeAnalysis.Diagnostics;
+
+namespace Microsoft.CodeAnalysis.Testing.TestAnalyzers
+{
+    internal class CSharpSuppressorTest<TAnalyzer, TSuppressor> : CSharpAnalyzerTest<TAnalyzer>
+        where TAnalyzer : DiagnosticAnalyzer, new()
+        where TSuppressor : DiagnosticSuppressor, new()
+    {
+        protected override IEnumerable<DiagnosticAnalyzer> GetDiagnosticAnalyzers()
+            => base.GetDiagnosticAnalyzers().Concat(new[] { new TSuppressor() });
+    }
+}
+
+#endif