Add incrementality tests

Author: Sergio0694

components/DependencyPropertyGenerator/CommunityToolkit.DependencyPropertyGenerator.Tests/Helpers/CSharpGeneratorTest{TGenerator}.cs

@@ -55,7 +55,7 @@ public static void VerifyDiagnostics(string source, params string[] diagnosticsI
     /// <param name="source">The input source to process.</param>
     /// <param name="result">The expected source to be generated.</param>
     /// <param name="languageVersion">The language version to use to run the test.</param>
-    public static void VerifySources(string source, (string Filename, string Source) result, LanguageVersion languageVersion = LanguageVersion.CSharp12)
+    public static void VerifySources(string source, (string Filename, string Source) result, LanguageVersion languageVersion = LanguageVersion.CSharp13)
     {
         RunGenerator(source, out Compilation compilation, out ImmutableArray<Diagnostic> diagnostics, languageVersion);
 
@@ -89,7 +89,7 @@ public static void VerifyIncrementalSteps(
         IncrementalStepRunReason outputReason,
         IncrementalStepRunReason? diagnosticsSourceReason,
         IncrementalStepRunReason sourceReason,
-        LanguageVersion languageVersion = LanguageVersion.CSharp12)
+        LanguageVersion languageVersion = LanguageVersion.CSharp13)
     {
         Compilation compilation = CreateCompilation(source, languageVersion);
 
@@ -173,7 +173,7 @@ public static void VerifyIncrementalSteps(
     /// <param name="source">The input source to process.</param>
     /// <param name="languageVersion">The language version to use to run the test.</param>
     /// <returns>The resulting <see cref="Compilation"/> object.</returns>
-    private static CSharpCompilation CreateCompilation(string source, LanguageVersion languageVersion = LanguageVersion.CSharp12)
+    private static CSharpCompilation CreateCompilation(string source, LanguageVersion languageVersion = LanguageVersion.CSharp13)
     {
         // Get all assembly references for the .NET TFM and ComputeSharp
         IEnumerable<MetadataReference> metadataReferences =
@@ -209,7 +209,7 @@ private static void RunGenerator(
         string source,
         out Compilation compilation,
         out ImmutableArray<Diagnostic> diagnostics,
-        LanguageVersion languageVersion = LanguageVersion.CSharp12)
+        LanguageVersion languageVersion = LanguageVersion.CSharp13)
     {
         Compilation originalCompilation = CreateCompilation(source, languageVersion);
 

components/DependencyPropertyGenerator/CommunityToolkit.DependencyPropertyGenerator.Tests/Test_DependencyPropertyGenerator_Incrementality.cs

@@ -0,0 +1,138 @@
+// 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 CommunityToolkit.GeneratedDependencyProperty.Tests.Helpers;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+namespace CommunityToolkit.GeneratedDependencyProperty.Tests;
+
+[TestClass]
+public class Test_DependencyPropertyGenerator_Incrementality
+{
+    [TestMethod]
+    public void ModifiedOptions_ModifiesOutput()
+    {
+        const string source = """"
+            using Windows.UI.Xaml;
+            using CommunityToolkit.WinUI;
+
+            namespace MyNamespace;
+
+            public partial class MyControl : DependencyObject
+            {
+                [GeneratedDependencyProperty]
+                public partial int Number { get; set; }
+            }
+            """";
+
+        const string updatedSource = """"
+            using Windows.UI.Xaml;
+            using CommunityToolkit.WinUI;
+
+            namespace MyNamespace;
+
+            public partial class MyControl : DependencyObject
+            {
+                [GeneratedDependencyProperty(DefaultValue = 42)]
+                public partial int Number { get; set; }
+            }
+            """";
+
+        CSharpGeneratorTest<DependencyPropertyGenerator>.VerifyIncrementalSteps(
+            source,
+            updatedSource,
+            executeReason: IncrementalStepRunReason.Modified,
+            diagnosticsReason: null,
+            outputReason: IncrementalStepRunReason.Modified,
+            diagnosticsSourceReason: null,
+            sourceReason: IncrementalStepRunReason.Modified);
+    }
+
+    [TestMethod]
+    public void AddedLeadingTrivia_DoesNotModifyOutput()
+    {
+        const string source = """"
+            using Windows.UI.Xaml;
+            using CommunityToolkit.WinUI;
+
+            namespace MyNamespace;
+
+            public partial class MyControl : DependencyObject
+            {
+                [GeneratedDependencyProperty]
+                public partial int Number { get; set; }
+            }
+            """";
+
+        const string updatedSource = """"
+            using Windows.UI.Xaml;
+            using CommunityToolkit.WinUI;
+
+            namespace MyNamespace;
+
+            public partial class MyControl : DependencyObject
+            {
+                /// <summary>
+                /// This is some property.
+                /// </summary>
+                [GeneratedDependencyProperty]
+                public partial int Number { get; set; }
+            }
+            """";
+
+        CSharpGeneratorTest<DependencyPropertyGenerator>.VerifyIncrementalSteps(
+            source,
+            updatedSource,
+            executeReason: IncrementalStepRunReason.Unchanged,
+            diagnosticsReason: null,
+            outputReason: IncrementalStepRunReason.Cached,
+            diagnosticsSourceReason: null,
+            sourceReason: IncrementalStepRunReason.Cached);
+    }
+
+    [TestMethod]
+    public void AddedOtherMember_DoesNotModifyOutput()
+    {
+        const string source = """"
+            using Windows.UI.Xaml;
+            using CommunityToolkit.WinUI;
+
+            namespace MyNamespace;
+
+            public partial class MyControl : DependencyObject
+            {
+                [GeneratedDependencyProperty]
+                public partial int Number { get; set; }
+            }
+            """";
+
+        const string updatedSource = """"
+            using Windows.UI.Xaml;
+            using CommunityToolkit.WinUI;
+
+            namespace MyNamespace;
+
+            public partial class MyControl : DependencyObject
+            {
+                public void Foo()
+                {
+                }
+
+                [GeneratedDependencyProperty]
+                public partial int Number { get; set; }
+            }
+            """";
+
+        CSharpGeneratorTest<DependencyPropertyGenerator>.VerifyIncrementalSteps(
+            source,
+            updatedSource,
+            executeReason: IncrementalStepRunReason.Unchanged,
+            diagnosticsReason: null,
+            outputReason: IncrementalStepRunReason.Cached,
+            diagnosticsSourceReason: null,
+            sourceReason: IncrementalStepRunReason.Cached);
+    }
+}