Implement analyzer and codefix to switch to Assert.ThrowsExactly[Async]

src/Analyzers/MSTest.Analyzers.CodeFixes/CodeFixResources.resx

@@ -168,4 +168,7 @@
   <data name="UseProperAssertMethodsFix" xml:space="preserve">
     <value>Use '{0}'</value>
   </data>
-</root>
+  <data name="UseNewerAssertThrows" xml:space="preserve">
+    <value>Use '{0}'</value>
+  </data>
+</root>

src/Analyzers/MSTest.Analyzers.CodeFixes/UseNewerAssertThrowsFixer.cs

@@ -0,0 +1,146 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System.Collections.Immutable;
+using System.Composition;
+
+using Analyzer.Utilities;
+
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CodeActions;
+using Microsoft.CodeAnalysis.CodeFixes;
+using Microsoft.CodeAnalysis.CSharp;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+using Microsoft.CodeAnalysis.Editing;
+
+using MSTest.Analyzers.Helpers;
+
+namespace MSTest.Analyzers;
+
+[ExportCodeFixProvider(LanguageNames.CSharp, Name = nameof(UseNewerAssertThrowsFixer))]
+[Shared]
+public sealed class UseNewerAssertThrowsFixer : CodeFixProvider
+{
+    public sealed override ImmutableArray<string> FixableDiagnosticIds { get; }
+        = ImmutableArray.Create(DiagnosticIds.UseNewerAssertThrowsRuleId);
+
+    public override FixAllProvider GetFixAllProvider()
+        // See https://github.com/dotnet/roslyn/blob/main/docs/analyzers/FixAllProvider.md for more information on Fix All Providers
+        => WellKnownFixAllProviders.BatchFixer;
+
+    public override async Task RegisterCodeFixesAsync(CodeFixContext context)
+    {
+        SyntaxNode root = await context.Document.GetRequiredSyntaxRootAsync(context.CancellationToken).ConfigureAwait(false);
+        Diagnostic diagnostic = context.Diagnostics[0];
+
+        SyntaxNode diagnosticNode = root.FindNode(diagnostic.Location.SourceSpan, getInnermostNodeForTie: true);
+        if (diagnosticNode is not InvocationExpressionSyntax invocation)
+        {
+            Debug.Fail($"Is this an interesting scenario where IInvocationOperation for Assert call isn't associated with InvocationExpressionSyntax? SyntaxNode type: '{diagnosticNode.GetType()}', Text: '{diagnosticNode.GetText()}'");
+            return;
+        }
+
+        SyntaxNode methodNameIdentifier = invocation.Expression;
+        if (methodNameIdentifier is MemberAccessExpressionSyntax memberAccess)
+        {
+            methodNameIdentifier = memberAccess.Name;
+        }
+
+        if (methodNameIdentifier is not GenericNameSyntax genericNameSyntax)
+        {
+            Debug.Fail($"Is this an interesting scenario where we are unable to retrieve GenericNameSyntax corresponding to the assert method? SyntaxNode type: '{methodNameIdentifier}', Text: '{methodNameIdentifier.GetText()}'.");
+            return;
+        }
+
+        string updatedMethodName = genericNameSyntax.Identifier.Text switch
+        {
+            "ThrowsException" => "ThrowsExactly",
+            "ThrowsExceptionAsync" => "ThrowsExactlyAsync",
+            // The analyzer should report a diagnostic only for ThrowsException and ThrowsExceptionAsync
+            _ => throw ApplicationStateGuard.Unreachable(),
+        };
+
+        context.RegisterCodeFix(
+            CodeAction.Create(
+                title: string.Format(CultureInfo.InvariantCulture, CodeFixResources.UseNewerAssertThrows, updatedMethodName),
+                ct => Task.FromResult(context.Document.WithSyntaxRoot(UpdateMethodName(new SyntaxEditor(root, context.Document.Project.Solution.Workspace), invocation, genericNameSyntax, updatedMethodName, diagnostic.AdditionalLocations))),
+                equivalenceKey: nameof(UseProperAssertMethodsFixer)),
+            diagnostic);
+    }
+
+    private static SyntaxNode UpdateMethodName(SyntaxEditor editor, InvocationExpressionSyntax invocation, GenericNameSyntax genericNameSyntax, string updatedMethodName, IReadOnlyList<Location> additionalLocations)
+    {
+        editor.ReplaceNode(genericNameSyntax, genericNameSyntax.WithIdentifier(SyntaxFactory.Identifier(updatedMethodName).WithTriviaFrom(genericNameSyntax.Identifier)));
+
+        // The object[] parameter to format the message is named parameters in the old ThrowsException[Async] methods, but is named messageArgs in the new ThrowsExactly[Async] methods.
+        if (invocation.ArgumentList.Arguments.FirstOrDefault(arg => arg.NameColon is { Name.Identifier.Text: "parameters" }) is { } arg)
+        {
+            editor.ReplaceNode(arg.NameColon!.Name, arg.NameColon!.Name.WithIdentifier(SyntaxFactory.Identifier("messageArgs").WithTriviaFrom(arg.NameColon.Name.Identifier)));
+        }
+
+        if (additionalLocations.Count == 1)
+        {
+            // The existing ThrowsException call is using the Func<object> overload. The new ThrowsExactly method does not have this overload, so we need to adjust.
+            // This is a best effort handling.
+            SyntaxNode actionArgument = editor.OriginalRoot.FindNode(additionalLocations[0].SourceSpan, getInnermostNodeForTie: true);
+
+            // If it's not ParenthesizedLambdaExpressionSyntax (e.g, a variable of type Func<object>), we can switch it to '() => _ = variableName()'
+            // But for now, we will only handle ParenthesizedLambdaExpressionSyntax.
+            if (actionArgument is ParenthesizedLambdaExpressionSyntax lambdaSyntax)
+            {
+                if (lambdaSyntax.ExpressionBody is not null)
+                {
+                    editor.ReplaceNode(
+                        lambdaSyntax.ExpressionBody,
+                        AssignToDiscard(lambdaSyntax.ExpressionBody));
+                }
+                else if (lambdaSyntax.Block is not null)
+                {
+                    // This is more complex. We need to iterate through all descendants of type ReturnStatementSyntax, and split it into two statements.
+                    // The first statement will be an assignment expression to a discard, and the second statement will be 'return;'.
+                    // We may even need to add extra braces in case the return statement (for example) is originally inside an if statement without braces.
+                    // For example:
+                    // if (condition)
+                    //     return Whatever;
+                    // should be converted to:
+                    // if (condition)
+                    // {
+                    //     _ = Whatever;
+                    //     return;
+                    // }
+                    // Keep in mind: When descending into descendant nodes, we shouldn't descend into potential other lambda expressions or local functions.
+                    IEnumerable<ReturnStatementSyntax> returnStatements = lambdaSyntax.Block.DescendantNodes(descendIntoChildren: node => node is not (LocalFunctionStatementSyntax or AnonymousFunctionExpressionSyntax)).OfType<ReturnStatementSyntax>();
+                    foreach (ReturnStatementSyntax returnStatement in returnStatements)
+                    {
+                        if (returnStatement.Expression is not { } returnExpression)
+                        {
+                            // This should be an error in user code.
+                            continue;
+                        }
+
+                        ExpressionStatementSyntax returnReplacement = SyntaxFactory.ExpressionStatement(AssignToDiscard(returnStatement.Expression));
+
+                        if (returnStatement.Parent is BlockSyntax blockSyntax)
+                        {
+                            editor.InsertAfter(returnStatement, SyntaxFactory.ReturnStatement());
+                            editor.ReplaceNode(returnStatement, returnReplacement);
+                        }
+                        else
+                        {
+                            editor.ReplaceNode(
+                                returnStatement,
+                                SyntaxFactory.Block(
+                                    returnReplacement,
+                                    SyntaxFactory.ReturnStatement()));
+                        }
+                    }
+                }
+            }
+        }
+
+        return editor.GetChangedRoot();
+    }
+
+    private static AssignmentExpressionSyntax AssignToDiscard(ExpressionSyntax expression)
+        => SyntaxFactory.AssignmentExpression(SyntaxKind.SimpleAssignmentExpression, SyntaxFactory.IdentifierName("_"), expression);
+}

src/Analyzers/MSTest.Analyzers.CodeFixes/xlf/CodeFixResources.cs.xlf

@@ -82,6 +82,11 @@
         <target state="translated">Přidat [TestMethod]</target>
         <note />
       </trans-unit>
+      <trans-unit id="UseNewerAssertThrows">
+        <source>Use '{0}'</source>
+        <target state="new">Use '{0}'</target>
+        <note />
+      </trans-unit>
       <trans-unit id="UseProperAssertMethodsFix">
         <source>Use '{0}'</source>
         <target state="translated">Použít {0}</target>

src/Analyzers/MSTest.Analyzers.CodeFixes/xlf/CodeFixResources.de.xlf

@@ -82,6 +82,11 @@
         <target state="translated">„[TestMethod]“ hinzufügen</target>
         <note />
       </trans-unit>
+      <trans-unit id="UseNewerAssertThrows">
+        <source>Use '{0}'</source>
+        <target state="new">Use '{0}'</target>
+        <note />
+      </trans-unit>
       <trans-unit id="UseProperAssertMethodsFix">
         <source>Use '{0}'</source>
         <target state="translated">"{0}" verwenden</target>

src/Analyzers/MSTest.Analyzers.CodeFixes/xlf/CodeFixResources.es.xlf

@@ -82,6 +82,11 @@
         <target state="translated">Agregar '[TestMethod]'</target>
         <note />
       </trans-unit>
+      <trans-unit id="UseNewerAssertThrows">
+        <source>Use '{0}'</source>
+        <target state="new">Use '{0}'</target>
+        <note />
+      </trans-unit>
       <trans-unit id="UseProperAssertMethodsFix">
         <source>Use '{0}'</source>
         <target state="translated">Usar "{0}"</target>

src/Analyzers/MSTest.Analyzers.CodeFixes/xlf/CodeFixResources.fr.xlf

@@ -82,6 +82,11 @@
         <target state="translated">Ajouter « [TestMethod] »</target>
         <note />
       </trans-unit>
+      <trans-unit id="UseNewerAssertThrows">
+        <source>Use '{0}'</source>
+        <target state="new">Use '{0}'</target>
+        <note />
+      </trans-unit>
       <trans-unit id="UseProperAssertMethodsFix">
         <source>Use '{0}'</source>
         <target state="translated">Utiliser « {0} »</target>

src/Analyzers/MSTest.Analyzers.CodeFixes/xlf/CodeFixResources.it.xlf

@@ -82,6 +82,11 @@
         <target state="translated">Aggiungi '[TestMethod]'</target>
         <note />
       </trans-unit>
+      <trans-unit id="UseNewerAssertThrows">
+        <source>Use '{0}'</source>
+        <target state="new">Use '{0}'</target>
+        <note />
+      </trans-unit>
       <trans-unit id="UseProperAssertMethodsFix">
         <source>Use '{0}'</source>
         <target state="translated">Usa '{0}'</target>

src/Analyzers/MSTest.Analyzers.CodeFixes/xlf/CodeFixResources.ja.xlf

@@ -82,6 +82,11 @@
         <target state="translated">'[TestMethod]' の追加</target>
         <note />
       </trans-unit>
+      <trans-unit id="UseNewerAssertThrows">
+        <source>Use '{0}'</source>
+        <target state="new">Use '{0}'</target>
+        <note />
+      </trans-unit>
       <trans-unit id="UseProperAssertMethodsFix">
         <source>Use '{0}'</source>
         <target state="translated">'{0}' を使用します</target>

src/Analyzers/MSTest.Analyzers.CodeFixes/xlf/CodeFixResources.ko.xlf

@@ -82,6 +82,11 @@
         <target state="translated">'[TestMethod]' 추가</target>
         <note />
       </trans-unit>
+      <trans-unit id="UseNewerAssertThrows">
+        <source>Use '{0}'</source>
+        <target state="new">Use '{0}'</target>
+        <note />
+      </trans-unit>
       <trans-unit id="UseProperAssertMethodsFix">
         <source>Use '{0}'</source>
         <target state="translated">'{0}' 사용</target>

src/Analyzers/MSTest.Analyzers.CodeFixes/xlf/CodeFixResources.pl.xlf

@@ -82,6 +82,11 @@
         <target state="translated">Dodaj „[TestMethod]”</target>
         <note />
       </trans-unit>
+      <trans-unit id="UseNewerAssertThrows">
+        <source>Use '{0}'</source>
+        <target state="new">Use '{0}'</target>
+        <note />
+      </trans-unit>
       <trans-unit id="UseProperAssertMethodsFix">
         <source>Use '{0}'</source>
         <target state="translated">Użyj „{0}”</target>

src/Analyzers/MSTest.Analyzers.CodeFixes/xlf/CodeFixResources.pt-BR.xlf

@@ -82,6 +82,11 @@
         <target state="translated">Adicionar ''[TestMethod]"</target>
         <note />
       </trans-unit>
+      <trans-unit id="UseNewerAssertThrows">
+        <source>Use '{0}'</source>
+        <target state="new">Use '{0}'</target>
+        <note />
+      </trans-unit>
       <trans-unit id="UseProperAssertMethodsFix">
         <source>Use '{0}'</source>
         <target state="translated">Usar '{0}'</target>

src/Analyzers/MSTest.Analyzers.CodeFixes/xlf/CodeFixResources.ru.xlf

@@ -82,6 +82,11 @@
         <target state="translated">Добавить "[TestMethod]"</target>
         <note />
       </trans-unit>
+      <trans-unit id="UseNewerAssertThrows">
+        <source>Use '{0}'</source>
+        <target state="new">Use '{0}'</target>
+        <note />
+      </trans-unit>
       <trans-unit id="UseProperAssertMethodsFix">
         <source>Use '{0}'</source>
         <target state="translated">Использовать "{0}"</target>

src/Analyzers/MSTest.Analyzers.CodeFixes/xlf/CodeFixResources.tr.xlf

@@ -82,6 +82,11 @@
         <target state="translated">'[TestMethod]' ekle</target>
         <note />
       </trans-unit>
+      <trans-unit id="UseNewerAssertThrows">
+        <source>Use '{0}'</source>
+        <target state="new">Use '{0}'</target>
+        <note />
+      </trans-unit>
       <trans-unit id="UseProperAssertMethodsFix">
         <source>Use '{0}'</source>
         <target state="translated">'{0}' kullan</target>

src/Analyzers/MSTest.Analyzers.CodeFixes/xlf/CodeFixResources.zh-Hans.xlf

@@ -82,6 +82,11 @@
         <target state="translated">添加“[TestMethod]”</target>
         <note />
       </trans-unit>
+      <trans-unit id="UseNewerAssertThrows">
+        <source>Use '{0}'</source>
+        <target state="new">Use '{0}'</target>
+        <note />
+      </trans-unit>
       <trans-unit id="UseProperAssertMethodsFix">
         <source>Use '{0}'</source>
         <target state="translated">使用“{0}”</target>

src/Analyzers/MSTest.Analyzers.CodeFixes/xlf/CodeFixResources.zh-Hant.xlf

@@ -82,6 +82,11 @@
         <target state="translated">新增 '[TestMethod]'</target>
         <note />
       </trans-unit>
+      <trans-unit id="UseNewerAssertThrows">
+        <source>Use '{0}'</source>
+        <target state="new">Use '{0}'</target>
+        <note />
+      </trans-unit>
       <trans-unit id="UseProperAssertMethodsFix">
         <source>Use '{0}'</source>
         <target state="translated">使用 '{0}'</target>

src/Analyzers/MSTest.Analyzers/AnalyzerReleases.Unshipped.md

@@ -1,2 +1,7 @@
 ; Unshipped analyzer release
 ; https://github.com/dotnet/roslyn-analyzers/blob/main/src/Microsoft.CodeAnalysis.Analyzers/ReleaseTrackingAnalyzers.Help.md
+### New Rules
+
+Rule ID | Category | Severity | Notes
+--------|----------|----------|-------
+MSTEST0038 | Usage | Info | UseNewerAssertThrowsAnalyzer

src/Analyzers/MSTest.Analyzers/Helpers/DiagnosticIds.cs

@@ -42,4 +42,5 @@ internal static class DiagnosticIds
     public const string UseDeploymentItemWithTestMethodOrTestClassRuleId = "MSTEST0035";
     public const string DoNotUseShadowingRuleId = "MSTEST0036";
     public const string UseProperAssertMethodsRuleId = "MSTEST0037";
+    public const string UseNewerAssertThrowsRuleId = "MSTEST0038";
 }

src/Analyzers/MSTest.Analyzers/Helpers/WellKnownTypeNames.cs

@@ -42,6 +42,7 @@ internal static class WellKnownTypeNames
     public const string System = "System";
     public const string SystemCollectionsGenericIEnumerable1 = "System.Collections.Generic.IEnumerable`1";
     public const string SystemDescriptionAttribute = "System.ComponentModel.DescriptionAttribute";
+    public const string SystemFunc1 = "System.Func`1";
     public const string SystemIAsyncDisposable = "System.IAsyncDisposable";
     public const string SystemIDisposable = "System.IDisposable";
     public const string SystemReflectionMethodInfo = "System.Reflection.MethodInfo";

src/Analyzers/MSTest.Analyzers/Resources.resx

@@ -543,4 +543,10 @@ The type declaring these methods should also respect the following rules:
   <data name="DynamicDataShouldBeValidMessageFormat_SourceTypeNotPropertyOrMethod" xml:space="preserve">
     <value>'[DynamicData]' member '{0}.{1}' is not a property nor a method. Only properties and methods are supported.</value>
   </data>
-</root>
+  <data name="UseNewerAssertThrowsTitle" xml:space="preserve">
+    <value>Use newer methods to assert exceptions</value>
+  </data>
+  <data name="UseNewerAssertThrowsMessageFormat" xml:space="preserve">
+    <value>Use 'Assert.ThrowsExactly' instead of 'Assert.ThrowsException'</value>
+  </data>
+</root>