Add CSharpAnalyzerWithLanguageVersionTest<TAnalyzer> test helper

Author: Sergio0694

tests/CommunityToolkit.Mvvm.SourceGenerators.UnitTests/CommunityToolkit.Mvvm.SourceGenerators.UnitTests.csproj

@@ -1,10 +1,11 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net472;netcoreapp3.1;net6.0</TargetFrameworks>
+    <TargetFramework>net6.0</TargetFramework>
   </PropertyGroup>
 
   <ItemGroup>
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Analyzer.Testing.MSTest" Version="1.1.1" />
     <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Workspaces" Version="4.0.1" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.0.0" />
     <PackageReference Include="MSTest.TestAdapter" Version="2.2.8" />

tests/CommunityToolkit.Mvvm.SourceGenerators.UnitTests/Helpers/CSharpAnalyzerWithLanguageVersionTest{TAnalyzer}.cs

@@ -0,0 +1,57 @@
+// 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.
+
+using System.Threading;
+using System.Threading.Tasks;
+using CommunityToolkit.Mvvm.ComponentModel;
+using Microsoft.CodeAnalysis.CSharp.Testing;
+using Microsoft.CodeAnalysis.CSharp;
+using Microsoft.CodeAnalysis.Diagnostics;
+using Microsoft.CodeAnalysis.Testing.Verifiers;
+using Microsoft.CodeAnalysis.Testing;
+using Microsoft.CodeAnalysis;
+
+namespace CommunityToolkit.Mvvm.SourceGenerators.UnitTests.Helpers;
+
+/// <summary>
+/// A custom <see cref="CSharpAnalyzerTest{TAnalyzer, TVerifier}"/> that uses a specific C# language version to parse code.
+/// </summary>
+/// <typeparam name="TAnalyzer">The type of the analyzer to test.</typeparam>
+internal sealed class CSharpAnalyzerWithLanguageVersionTest<TAnalyzer> : CSharpAnalyzerTest<TAnalyzer, MSTestVerifier>
+    where TAnalyzer : DiagnosticAnalyzer, new()
+{
+    /// <summary>
+    /// The C# language version to use to parse code.
+    /// </summary>
+    private readonly LanguageVersion languageVersion;
+
+    /// <summary>
+    /// Creates a new <see cref="CSharpAnalyzerWithLanguageVersionTest{TAnalyzer}"/> instance with the specified paramaters.
+    /// </summary>
+    /// <param name="languageVersion">The C# language version to use to parse code.</param>
+    private CSharpAnalyzerWithLanguageVersionTest(LanguageVersion languageVersion)
+    {
+        this.languageVersion = languageVersion;
+    }
+
+    /// <inheritdoc/>
+    protected override ParseOptions CreateParseOptions()
+    {
+        return new CSharpParseOptions(this.languageVersion, DocumentationMode.Diagnose);
+    }
+
+    /// <inheritdoc cref="AnalyzerVerifier{TAnalyzer, TTest, TVerifier}.VerifyAnalyzerAsync"/>
+    /// <param name="languageVersion">The language version to use to run the test.</param>
+    public static Task VerifyAnalyzerAsync(string source, LanguageVersion languageVersion, params DiagnosticResult[] expected)
+    {
+        CSharpAnalyzerWithLanguageVersionTest<TAnalyzer> test = new(languageVersion) { TestCode = source };
+
+        test.TestState.ReferenceAssemblies = ReferenceAssemblies.Net.Net60;
+        test.TestState.AdditionalReferences.Add(MetadataReference.CreateFromFile(typeof(ObservableObject).Assembly.Location));
+
+        test.ExpectedDiagnostics.AddRange(expected);
+
+        return test.RunAsync(CancellationToken.None);
+    }
+}