Migrate from xUnit to NUnit 4.4.0 with concurrency configuration

Co-authored-by: glennawatson <[email protected]>

Author: Copilot

.editorconfig

@@ -552,4 +552,116 @@ end_of_line = lf
 [*.{cmd, bat}]
 end_of_line = crlf
 
+#############################################
+# NUnit Analyzers — enable all as errors
+#############################################
+
+# Structure Rules (NUnit1001 - )
+dotnet_diagnostic.NUnit1001.severity = error # TestCase args must match parameter types
+dotnet_diagnostic.NUnit1002.severity = error # TestCaseSource should use nameof
+dotnet_diagnostic.NUnit1003.severity = error # TestCase provided too few arguments
+dotnet_diagnostic.NUnit1004.severity = error # TestCase provided too many arguments
+dotnet_diagnostic.NUnit1005.severity = error # ExpectedResult type must match return type
+dotnet_diagnostic.NUnit1006.severity = error # ExpectedResult must not be used on void methods
+dotnet_diagnostic.NUnit1007.severity = error # Non-void method but no ExpectedResult provided
+dotnet_diagnostic.NUnit1008.severity = error # ParallelScope.Self at assembly level has no effect
+dotnet_diagnostic.NUnit1009.severity = error # ParallelScope.Children on non-parameterized test
+dotnet_diagnostic.NUnit1010.severity = error # ParallelScope.Fixtures on a test method
+dotnet_diagnostic.NUnit1011.severity = error # TestCaseSource member does not exist
+dotnet_diagnostic.NUnit1012.severity = error # async test method must have non-void return type
+dotnet_diagnostic.NUnit1013.severity = error # async method must use non-generic Task when no result
+dotnet_diagnostic.NUnit1014.severity = error # async method must use Task<T> when result expected
+dotnet_diagnostic.NUnit1015.severity = error # Source type does not implement I(Async)Enumerable
+dotnet_diagnostic.NUnit1016.severity = error # Source type lacks default constructor
+dotnet_diagnostic.NUnit1017.severity = error # Specified source is not static
+dotnet_diagnostic.NUnit1018.severity = error # TestCaseSource param count mismatch (target method)
+dotnet_diagnostic.NUnit1019.severity = error # Source does not return I(Async)Enumerable
+dotnet_diagnostic.NUnit1020.severity = error # Parameters provided to field/property source
+dotnet_diagnostic.NUnit1021.severity = error # ValueSource should use nameof
+dotnet_diagnostic.NUnit1022.severity = error # Specified ValueSource is not static
+dotnet_diagnostic.NUnit1023.severity = error # ValueSource cannot supply required parameters
+dotnet_diagnostic.NUnit1024.severity = error # ValueSource does not return I(Async)Enumerable
+dotnet_diagnostic.NUnit1025.severity = error # ValueSource member does not exist
+dotnet_diagnostic.NUnit1026.severity = error # Test or setup/teardown method is not public
+dotnet_diagnostic.NUnit1027.severity = error # Test method has parameters but no arguments supplied
+dotnet_diagnostic.NUnit1028.severity = error # Non-test method is public
+dotnet_diagnostic.NUnit1029.severity = error # TestCaseSource param count mismatch (Test method)
+dotnet_diagnostic.NUnit1030.severity = error # TestCaseSource parameter type mismatch (Test method)
+dotnet_diagnostic.NUnit1031.severity = error # ValuesAttribute args must match parameter types
+dotnet_diagnostic.NUnit1032.severity = error # IDisposable field/property should be disposed in TearDown
+dotnet_diagnostic.NUnit1033.severity = error # TestContext.Write methods will be obsolete
+dotnet_diagnostic.NUnit1034.severity = error # Base TestFixtures should be abstract
+dotnet_diagnostic.NUnit1035.severity = error # Range 'step' parameter cannot be zero
+dotnet_diagnostic.NUnit1036.severity = error # Range: from < to when step is positive
+dotnet_diagnostic.NUnit1037.severity = error # Range: from > to when step is negative
+dotnet_diagnostic.NUnit1038.severity = error # Attribute values' types must match parameter type
+
+# Assertion Rules (NUnit2001 - )
+dotnet_diagnostic.NUnit2001.severity = error # Prefer Assert.That(..., Is.False) over ClassicAssert.False
+dotnet_diagnostic.NUnit2002.severity = error # Prefer Assert.That(..., Is.False) over ClassicAssert.IsFalse
+dotnet_diagnostic.NUnit2003.severity = error # Prefer Assert.That(..., Is.True) over ClassicAssert.IsTrue
+dotnet_diagnostic.NUnit2004.severity = error # Prefer Assert.That(..., Is.True) over ClassicAssert.True
+dotnet_diagnostic.NUnit2005.severity = error # Prefer Is.EqualTo over AreEqual
+dotnet_diagnostic.NUnit2006.severity = error # Prefer Is.Not.EqualTo over AreNotEqual
+dotnet_diagnostic.NUnit2007.severity = error # Actual value should not be a constant
+dotnet_diagnostic.NUnit2008.severity = error # Incorrect IgnoreCase usage
+dotnet_diagnostic.NUnit2009.severity = error # Same value used for actual and expected
+dotnet_diagnostic.NUnit2010.severity = error # Use EqualConstraint for better messages
+dotnet_diagnostic.NUnit2011.severity = error # Use ContainsConstraint for better messages
+dotnet_diagnostic.NUnit2012.severity = error # Use StartsWithConstraint for better messages
+dotnet_diagnostic.NUnit2013.severity = error # Use EndsWithConstraint for better messages
+dotnet_diagnostic.NUnit2014.severity = error # Use SomeItemsConstraint for better messages
+dotnet_diagnostic.NUnit2015.severity = error # Prefer Is.SameAs over AreSame
+dotnet_diagnostic.NUnit2016.severity = error # Prefer Is.Null over ClassicAssert.Null
+dotnet_diagnostic.NUnit2017.severity = error # Prefer Is.Null over ClassicAssert.IsNull
+dotnet_diagnostic.NUnit2018.severity = error # Prefer Is.Not.Null over ClassicAssert.NotNull
+dotnet_diagnostic.NUnit2019.severity = error # Prefer Is.Not.Null over ClassicAssert.IsNotNull
+dotnet_diagnostic.NUnit2020.severity = error # Incompatible types for SameAs constraint
+dotnet_diagnostic.NUnit2021.severity = error # Incompatible types for EqualTo constraint
+dotnet_diagnostic.NUnit2022.severity = error # Missing property required for constraint
+dotnet_diagnostic.NUnit2023.severity = error # Invalid NullConstraint usage
+dotnet_diagnostic.NUnit2024.severity = error # Wrong actual type with String constraint
+dotnet_diagnostic.NUnit2025.severity = error # Wrong actual type with ContainsConstraint
+dotnet_diagnostic.NUnit2026.severity = error # Wrong actual type with SomeItems+EqualConstraint
+dotnet_diagnostic.NUnit2027.severity = error # Prefer Is.GreaterThan over ClassicAssert.Greater
+dotnet_diagnostic.NUnit2028.severity = error # Prefer Is.GreaterThanOrEqualTo over GreaterOrEqual
+dotnet_diagnostic.NUnit2029.severity = error # Prefer Is.LessThan over ClassicAssert.Less
+dotnet_diagnostic.NUnit2030.severity = error # Prefer Is.LessThanOrEqualTo over LessOrEqual
+dotnet_diagnostic.NUnit2031.severity = error # Prefer Is.Not.SameAs over AreNotSame
+dotnet_diagnostic.NUnit2032.severity = error # Prefer Is.Zero over ClassicAssert.Zero
+dotnet_diagnostic.NUnit2033.severity = error # Prefer Is.Not.Zero over ClassicAssert.NotZero
+dotnet_diagnostic.NUnit2034.severity = error # Prefer Is.NaN over ClassicAssert.IsNaN
+dotnet_diagnostic.NUnit2035.severity = error # Prefer Is.Empty over ClassicAssert.IsEmpty
+dotnet_diagnostic.NUnit2036.severity = error # Prefer Is.Not.Empty over ClassicAssert.IsNotEmpty
+dotnet_diagnostic.NUnit2037.severity = error # Prefer Does.Contain over ClassicAssert.Contains
+dotnet_diagnostic.NUnit2038.severity = error # Prefer Is.InstanceOf over ClassicAssert.IsInstanceOf
+dotnet_diagnostic.NUnit2039.severity = error # Prefer Is.Not.InstanceOf over ClassicAssert.IsNotInstanceOf
+dotnet_diagnostic.NUnit2040.severity = error # Non-reference types for SameAs constraint
+dotnet_diagnostic.NUnit2041.severity = error # Incompatible types for comparison constraint
+dotnet_diagnostic.NUnit2042.severity = error # Comparison constraint on object
+dotnet_diagnostic.NUnit2043.severity = error # Use ComparisonConstraint for better messages
+dotnet_diagnostic.NUnit2044.severity = error # Non-delegate actual parameter
+dotnet_diagnostic.NUnit2045.severity = error # Use Assert.EnterMultipleScope or Assert.Multiple
+dotnet_diagnostic.NUnit2046.severity = error # Use CollectionConstraint for better messages
+dotnet_diagnostic.NUnit2047.severity = error # Incompatible types for Within constraint
+dotnet_diagnostic.NUnit2048.severity = error # Prefer Assert.That over StringAssert
+dotnet_diagnostic.NUnit2049.severity = error # Prefer Assert.That over CollectionAssert
+dotnet_diagnostic.NUnit2050.severity = error # NUnit 4 no longer supports string.Format spec
+dotnet_diagnostic.NUnit2051.severity = error # Prefer Is.Positive over ClassicAssert.Positive
+dotnet_diagnostic.NUnit2052.severity = error # Prefer Is.Negative over ClassicAssert.Negative
+dotnet_diagnostic.NUnit2053.severity = error # Prefer Is.AssignableFrom over ClassicAssert.IsAssignableFrom
+dotnet_diagnostic.NUnit2054.severity = error # Prefer Is.Not.AssignableFrom over ClassicAssert.IsNotAssignableFrom
+dotnet_diagnostic.NUnit2055.severity = error # Prefer Is.InstanceOf<T> over 'is T' expression
+dotnet_diagnostic.NUnit2056.severity = error # Prefer Assert.EnterMultipleScope statement over Multiple
+
+# Suppressor Rules (NUnit3001 - )
+dotnet_diagnostic.NUnit3001.severity = error # Expression checked in NotNull/IsNotNull/Assert.That
+dotnet_diagnostic.NUnit3002.severity = error # Field/Property initialized in SetUp/OneTimeSetUp
+dotnet_diagnostic.NUnit3003.severity = error # TestFixture instantiated via reflection
+dotnet_diagnostic.NUnit3004.severity = error # Field should be disposed in TearDown/OneTimeTearDown
+
+# Style Rules (NUnit4001 - )
+dotnet_diagnostic.NUnit4001.severity = error # Simplify the Values attribute
+dotnet_diagnostic.NUnit4002.severity = error # Use Specific constraint
+
 vsspell_dictionary_languages = en-US

src/Directory.Packages.props

@@ -32,15 +32,13 @@
     <PackageVersion Include="ReactiveUI.Maui" Version="22.1.1" />
     <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.0.0" />
     <PackageVersion Include="System.Formats.Asn1" Version="9.0.0" />
-    <PackageVersion Include="xunit" Version="2.9.3" />
-    <PackageVersion Include="xunit.runner.console" Version="2.9.3" />
-    <PackageVersion Include="xunit.runner.visualstudio" Version="3.1.5" />
-    <PackageVersion Include="Xunit.StaFact" Version="3.0.13" />
-    <PackageVersion Include="FluentAssertions" Version="8.7.1" />
+    <PackageVersion Include="NUnit" Version="4.4.0" />
+    <PackageVersion Include="NUnit3TestAdapter" Version="5.2.0" />
+    <PackageVersion Include="NUnit.Analyzers" Version="4.5.0" />
     <PackageVersion Include="Microsoft.Reactive.Testing" Version="6.1.0" />
     <PackageVersion Include="PublicApiGenerator" Version="11.5.0" />
     <PackageVersion Include="coverlet.msbuild" Version="6.0.4" />
-    <PackageVersion Include="Verify.Xunit" Version="31.0.2" />
+    <PackageVersion Include="Verify.NUnit" Version="31.0.2" />
     <PackageVersion Include="Verify.SourceGenerators" Version="2.5.0" />
     <PackageVersion Include="ReactiveMarbles.SourceGenerator.TestNuGetHelper" Version="1.3.1" />
     <PackageVersion Include="Basic.Reference.Assemblies.Net80" Version="1.8.3" />

src/ReactiveUI.SourceGenerator.Tests/AssemblyInfo.Parallel.cs

@@ -0,0 +1,9 @@
+// Copyright (c) 2025 ReactiveUI and contributors. All rights reserved.
+// Licensed to the ReactiveUI and contributors under one or more agreements.
+// The ReactiveUI and contributors licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for full license information.
+
+using NUnit.Framework;
+
+[assembly: Parallelizable(ParallelScope.Fixtures)]
+[assembly: LevelOfParallelism(4)]

src/ReactiveUI.SourceGenerator.Tests/ReactiveUI.SourceGenerators.Tests.csproj

@@ -16,22 +16,22 @@
     <PackageReference Include="NuGet.Common" />
     <PackageReference Include="NuGet.Protocol" />
     <PackageReference Include="System.Formats.Asn1" />
-    <PackageReference Include="xunit" />
-    <PackageReference Include="xunit.runner.visualstudio" />
+    <PackageReference Include="NUnit" />
+    <PackageReference Include="NUnit3TestAdapter" />
+    <PackageReference Include="NUnit.Analyzers" />
     <PackageReference Include="ReactiveMarbles.SourceGenerator.TestNuGetHelper" />
-    <PackageReference Include="Verify.Xunit" />
+    <PackageReference Include="Verify.NUnit" />
     <PackageReference Include="Verify.SourceGenerators" />
     <PackageReference Include="Basic.Reference.Assemblies.Net80" />
     <PackageReference Include="Microsoft.CodeAnalysis.CSharp" PrivateAssets="all" VersionOverride="4.12.0" />
     <PackageReference Include="Microsoft.CodeAnalysis.Common" PrivateAssets="all" VersionOverride="4.12.0" />
     <PackageReference Include="Microsoft.CodeAnalysis.Workspaces.Common" PrivateAssets="all" VersionOverride="4.12.0" />
     <PackageReference Include="Microsoft.CodeAnalysis" PrivateAssets="all" VersionOverride="4.12.0" />
     <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Workspaces" PrivateAssets="all" VersionOverride="4.12.0" />
-    <PackageReference Include="FluentAssertions" />
   </ItemGroup>
 
   <ItemGroup>
-    <Using Include="Xunit" />
+    <Using Include="NUnit.Framework" />
   </ItemGroup>
 
   <ItemGroup>

src/ReactiveUI.SourceGenerator.Tests/TestBase.cs

@@ -4,33 +4,36 @@
 // See the LICENSE file in the project root for full license information.
 
 using Microsoft.CodeAnalysis;
-using Xunit.Abstractions;
 
 namespace ReactiveUI.SourceGenerator.Tests;
 
 /// <summary>
 /// A base class for handling test setup and teardown.
 /// </summary>
 /// <typeparam name="T">Type of Incremental Generator.</typeparam>
-/// <seealso cref="Xunit.IAsyncLifetime" />
 /// <seealso cref="System.IDisposable" />
-/// <param name="testOutputHelper">The output helper.</param>
-public abstract class TestBase<T>(ITestOutputHelper testOutputHelper) : IAsyncLifetime, IDisposable
+public abstract class TestBase<T> : IDisposable
         where T : IIncrementalGenerator, new()
 {
     /// <summary>
     /// Gets the TestHelper instance.
     /// </summary>
-    protected TestHelper<T> TestHelper { get; } = new(testOutputHelper);
+    protected TestHelper<T> TestHelper { get; } = new();
 
-    /// <inheritdoc/>
+    /// <summary>
+    /// Initializes the test helper asynchronously.
+    /// </summary>
+    /// <returns>A task representing the asynchronous operation.</returns>
+    [OneTimeSetUp]
     public Task InitializeAsync() => TestHelper.InitializeAsync();
 
-    /// <inheritdoc/>
-    public Task DisposeAsync()
+    /// <summary>
+    /// Disposes the test helper.
+    /// </summary>
+    [OneTimeTearDown]
+    public void DisposeAsync()
     {
         TestHelper.Dispose();
-        return Task.CompletedTask;
     }
 
     /// <inheritdoc/>

src/ReactiveUI.SourceGenerator.Tests/TestHelper.cs

@@ -3,8 +3,6 @@
 // The ReactiveUI and contributors licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for full license information.
 
-using FluentAssertions;
-
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CSharp;
 
@@ -19,7 +17,7 @@
 using ReactiveUI.SourceGenerators;
 using ReactiveUI.SourceGenerators.WinForms;
 
-using Xunit.Abstractions;
+using NUnit.Framework;
 
 namespace ReactiveUI.SourceGenerator.Tests;
 
@@ -29,8 +27,7 @@ namespace ReactiveUI.SourceGenerator.Tests;
 /// </summary>
 /// <typeparam name="T">Type of Incremental Generator.</typeparam>
 /// <seealso cref="System.IDisposable" />
-/// <param name="testOutput">The test output helper for capturing test logs.</param>
-public sealed class TestHelper<T>(ITestOutputHelper testOutput) : IDisposable
+public sealed class TestHelper<T> : IDisposable
         where T : IIncrementalGenerator, new()
 {
 #pragma warning disable CS0618 // Type or member is obsolete
@@ -127,7 +124,7 @@ public void TestFail(
             throw new InvalidOperationException("Must have valid compiler instance.");
         }
 
-        var utility = new SourceGeneratorUtility(x => testOutput.WriteLine(x));
+        var utility = new SourceGeneratorUtility(x => TestContext.Out.WriteLine(x));
 
 #pragma warning disable IDE0053 // Use expression body for lambda expression
 #pragma warning disable RCS1021 // Convert lambda expression body to expression body
@@ -204,7 +201,7 @@ public SettingsTask RunGeneratorAndCheck(
             var prediagnostics = compilation.GetDiagnostics()
                 .Where(d => d.Severity > DiagnosticSeverity.Warning)
                 .ToList();
-            prediagnostics.Should().BeEmpty();
+            Assert.That(prediagnostics, Is.Empty);
         }
 
         var generator = new T();
@@ -224,7 +221,7 @@ public SettingsTask RunGeneratorAndCheck(
             {
                 foreach (var diagnostic in offendingDiagnostics)
                 {
-                    testOutput.WriteLine($"Diagnostic: {diagnostic.Id} - {diagnostic.GetMessage()}");
+                    TestContext.Out.WriteLine($"Diagnostic: {diagnostic.Id} - {diagnostic.GetMessage()}");
                 }
 
                 throw new InvalidOperationException("Compilation failed due to the above diagnostics.");

src/ReactiveUI.SourceGenerator.Tests/UnitTests/BindableDerivedListGeneratorTests.cs

@@ -4,20 +4,20 @@
 // See the LICENSE file in the project root for full license information.
 
 using ReactiveUI.SourceGenerators;
-using Xunit.Abstractions;
 
 namespace ReactiveUI.SourceGenerator.Tests;
 
 /// <summary>
 /// BindableDerivedListGeneratorTests.
 /// </summary>
-public class BindableDerivedListGeneratorTests(ITestOutputHelper output) : TestBase<BindableDerivedListGenerator>(output)
+[TestFixture]
+public class BindableDerivedListGeneratorTests : TestBase<BindableDerivedListGenerator>
 {
     /// <summary>
     /// Tests that the source generator correctly generates reactive properties.
     /// </summary>
     /// <returns>A task to monitor the async.</returns>
-    [Fact]
+    [Test]
     public Task FromReactiveProperties()
     {
         // Arrange: Setup the source code that matches the generator input expectations.

src/ReactiveUI.SourceGenerator.Tests/UnitTests/IViewForGeneratorTests.cs

@@ -4,20 +4,20 @@
 // See the LICENSE file in the project root for full license information.
 
 using ReactiveUI.SourceGenerators;
-using Xunit.Abstractions;
 
 namespace ReactiveUI.SourceGenerator.Tests;
 
 /// <summary>
 /// IViewForGeneratorTests.
 /// </summary>
-public class IViewForGeneratorTests(ITestOutputHelper output) : TestBase<IViewForGenerator>(output)
+[TestFixture]
+public class IViewForGeneratorTests : TestBase<IViewForGenerator>
 {
     /// <summary>
     /// Tests that the source generator correctly generates reactive properties.
     /// </summary>
     /// <returns>A task to monitor the async.</returns>
-    [Fact]
+    [Test]
     public Task FromIViewFor()
     {
         // Arrange: Setup the source code that matches the generator input expectations.