Add DependencyModules.xUnit4 for xunit.v3 4.x

.github/workflows/build-package.yaml

@@ -70,6 +70,11 @@ jobs:
           name: coverage-report
           path: artifacts/coverage
 
+      # The coverage run is on xunit.v3 3.x. This runs the xUnit tests again on 4.x, against
+      # DependencyModules.xUnit4.
+      - name: Test on xunit.v3 4.x
+        run: ./scripts/test-xunit.sh 4
+
       # Packs and consumes the packages the way a real user would. Catches packaging faults
       # that a ProjectReference-based test suite cannot see.
       - name: Verify packages

.github/workflows/release.yaml

@@ -74,6 +74,9 @@ jobs:
             cat artifacts/coverage/SummaryGithub.md >> "$GITHUB_STEP_SUMMARY"
           fi
 
+      - name: Test on xunit.v3 4.x
+        run: ./scripts/test-xunit.sh 4
+
       - name: Verify packages
         run: ./scripts/verify-packages.sh "${{ steps.version.outputs.version }}"
 
@@ -86,6 +89,7 @@ jobs:
             src/DependencyModules.SourceGenerator.Impl/DependencyModules.SourceGenerator.Impl.csproj \
             src/DependencyModules.Testing/DependencyModules.Testing.csproj \
             src/DependencyModules.xUnit/DependencyModules.xUnit.csproj \
+            src/DependencyModules.xUnit4/DependencyModules.xUnit4.csproj \
             src/DependencyModules.NUnit/DependencyModules.NUnit.csproj \
             src/DependencyModules.NSubstitute/DependencyModules.NSubstitute.csproj \
             src/DependencyModules.Moq/DependencyModules.Moq.csproj \

.github/workflows/xunit-prerelease.yaml

@@ -0,0 +1,50 @@
+name: xunit-prerelease
+
+# Runs the xUnit tests against the newest xunit.v3 on nuget.org, prereleases included. xUnit ships
+# prereleases of a major for months before the release, and the 4.0 breaks were in them: the first
+# on 2026-04-12, four months before 4.0.0. A failure here is notice of a coming break. Without it,
+# the first report comes from a consumer.
+on:
+  schedule:
+    - cron: '0 6 * * 1'
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      # See build-package.yaml: the 10.0 SDK builds, the 8.0 runtime runs the net8.0 tests.
+      - uses: actions/setup-dotnet@v4
+        with:
+          dotnet-version: |
+            8.0.x
+            10.0.x
+
+      - name: Find the newest xunit.v3 and runner
+        id: versions
+        run: |
+          newest() {
+            curl -fsSL "https://api.nuget.org/v3-flatcontainer/$1/index.json" | python3 -c '
+          import json, sys
+
+          def precedence(version):
+              release, _, prerelease = version.partition("-")
+              numbers = [int(part) for part in release.split(".")]
+              if not prerelease:
+                  return (numbers, 1, [])
+              return (numbers, 0, [(0, int(part), "") if part.isdigit() else (1, 0, part) for part in prerelease.split(".")])
+
+          print(max(json.load(sys.stdin)["versions"], key=precedence))
+          '
+          }
+          echo "xunit=$(newest xunit.v3.mtp-off)" >> "$GITHUB_OUTPUT"
+          echo "runner=$(newest xunit.runner.visualstudio)" >> "$GITHUB_OUTPUT"
+
+      # 4 is the newest DependencyModules xUnit build. Raise it when a build for a new major is added.
+      - name: Test on xunit.v3.mtp-off ${{ steps.versions.outputs.xunit }}
+        run: ./scripts/test-xunit.sh 4 "${{ steps.versions.outputs.xunit }}" "${{ steps.versions.outputs.runner }}"

CONTRIBUTING.md

@@ -22,7 +22,15 @@ To run all tests with code coverage, use the coverage script. The script writes
 ./scripts/coverage.sh 85
 ```
 
-To do a test of the packages that a user gets, use the package script. The script packs the nine packages. Then it builds and runs a test application for each target framework. The test application references these packages.
+The xUnit test projects use `xunit.v3` version 3 and `DependencyModules.xUnit`. To run them with `xunit.v3` version 4 and `DependencyModules.xUnit4`, use the xUnit script:
+
+```shell
+./scripts/test-xunit.sh 4
+```
+
+The `XunitMajor` property in `Directory.Build.props` selects the version. The script sets it to the major version that you give.
+
+To do a test of the packages that a user gets, use the package script. The script packs the ten packages. Then it builds and runs a test application for each target framework. The test application references these packages.
 
 ```shell
 ./scripts/verify-packages.sh
@@ -63,7 +71,10 @@ The `build-package` workflow runs for each pull request to `main`. It does these
 1. It does a check of the format with CSharpier.
 2. It builds the solution.
 3. It runs all tests with code coverage. The line coverage must be 85 percent or more.
-4. It runs `scripts/verify-packages.sh`.
+4. It runs the xUnit tests again with `xunit.v3` version 4.
+5. It runs `scripts/verify-packages.sh`.
+
+The `xunit-prerelease` workflow runs each week. It runs the xUnit tests with the newest `xunit.v3` on nuget.org, prereleases included. A failure tells you about a change in xUnit before its release.
 
 ## Documentation
 
@@ -96,8 +107,8 @@ git push origin v1.5.0
 The `release` workflow then does these steps:
 
 1. It builds the code.
-2. It runs the tests.
-3. It packs the nine packages.
+2. It runs the tests with `xunit.v3` version 3 and version 4.
+3. It packs the ten packages.
 4. It publishes the packages to nuget.org and to GitHub Packages.
 5. It makes a GitHub release with generated release notes.
 

DependencyModules.sln

@@ -46,6 +46,8 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "DependencyModules.NUnit", "
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "SutProject.NUnitTests", "integ-tests\SutProject.NUnitTests\SutProject.NUnitTests.csproj", "{C3B5B8CE-D219-42C8-A1B8-5C283C053E98}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "DependencyModules.xUnit4", "src\DependencyModules.xUnit4\DependencyModules.xUnit4.csproj", "{D1AEA1C9-CD76-4664-956B-706962E78E3D}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -272,6 +274,18 @@ Global
 		{C3B5B8CE-D219-42C8-A1B8-5C283C053E98}.Release|x64.Build.0 = Release|Any CPU
 		{C3B5B8CE-D219-42C8-A1B8-5C283C053E98}.Release|x86.ActiveCfg = Release|Any CPU
 		{C3B5B8CE-D219-42C8-A1B8-5C283C053E98}.Release|x86.Build.0 = Release|Any CPU
+		{D1AEA1C9-CD76-4664-956B-706962E78E3D}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{D1AEA1C9-CD76-4664-956B-706962E78E3D}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{D1AEA1C9-CD76-4664-956B-706962E78E3D}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{D1AEA1C9-CD76-4664-956B-706962E78E3D}.Debug|x64.Build.0 = Debug|Any CPU
+		{D1AEA1C9-CD76-4664-956B-706962E78E3D}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{D1AEA1C9-CD76-4664-956B-706962E78E3D}.Debug|x86.Build.0 = Debug|Any CPU
+		{D1AEA1C9-CD76-4664-956B-706962E78E3D}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{D1AEA1C9-CD76-4664-956B-706962E78E3D}.Release|Any CPU.Build.0 = Release|Any CPU
+		{D1AEA1C9-CD76-4664-956B-706962E78E3D}.Release|x64.ActiveCfg = Release|Any CPU
+		{D1AEA1C9-CD76-4664-956B-706962E78E3D}.Release|x64.Build.0 = Release|Any CPU
+		{D1AEA1C9-CD76-4664-956B-706962E78E3D}.Release|x86.ActiveCfg = Release|Any CPU
+		{D1AEA1C9-CD76-4664-956B-706962E78E3D}.Release|x86.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -296,5 +310,6 @@ Global
 		{DB6B8603-CBA7-443D-AEA9-E37BF61AD1B7} = {FB161494-E422-4D4E-BA04-3473C2EB13B0}
 		{F911E2B7-4D5A-4DC2-9E3E-4B2CFC30CF4E} = {FB161494-E422-4D4E-BA04-3473C2EB13B0}
 		{C3B5B8CE-D219-42C8-A1B8-5C283C053E98} = {DC7C95FE-F58F-4F16-8DFA-87E1B67DCEAE}
+		{D1AEA1C9-CD76-4664-956B-706962E78E3D} = {FB161494-E422-4D4E-BA04-3473C2EB13B0}
 	EndGlobalSection
 EndGlobal

Directory.Build.props

@@ -35,6 +35,31 @@
         <LibraryTargetFrameworks>net8.0;net10.0</LibraryTargetFrameworks>
     </PropertyGroup>
 
+    <!--
+        The xunit.v3 major that the xUnit test projects build and run against. CI runs both, through
+        scripts/test-xunit.sh for the second. 4 uses xunit.v3.mtp-off, not xunit.v3: the
+        Microsoft.Testing.Platform v2 that xunit.v3 4.x brings refuses the VSTest `dotnet test` on
+        the .NET 10 SDK, and xUnit ships mtp-off for exactly that. XunitV3Version and
+        XunitRunnerVersion can be set from the command line, which the prerelease workflow does.
+    -->
+    <PropertyGroup>
+        <XunitMajor Condition="'$(XunitMajor)' == ''">3</XunitMajor>
+    </PropertyGroup>
+
+    <PropertyGroup Condition="'$(XunitMajor)' == '3'">
+        <XunitV3Package>xunit.v3</XunitV3Package>
+        <XunitV3Version Condition="'$(XunitV3Version)' == ''">3.2.2</XunitV3Version>
+        <XunitRunnerVersion Condition="'$(XunitRunnerVersion)' == ''">3.1.5</XunitRunnerVersion>
+        <DependencyModulesXunitProject>DependencyModules.xUnit</DependencyModulesXunitProject>
+    </PropertyGroup>
+
+    <PropertyGroup Condition="'$(XunitMajor)' == '4'">
+        <XunitV3Package>xunit.v3.mtp-off</XunitV3Package>
+        <XunitV3Version Condition="'$(XunitV3Version)' == ''">4.0.1</XunitV3Version>
+        <XunitRunnerVersion Condition="'$(XunitRunnerVersion)' == ''">4.0.0</XunitRunnerVersion>
+        <DependencyModulesXunitProject>DependencyModules.xUnit4</DependencyModulesXunitProject>
+    </PropertyGroup>
+
     <PropertyGroup>
         <Authors>Ian Johnson</Authors>
         <Company>Ian Johnson</Company>

README.md

@@ -107,9 +107,10 @@ The `integ-tests` folder contains projects that reference the source projects of
 | --- | --- |
 | [DependencyModules.Runtime](https://www.nuget.org/packages/DependencyModules.Runtime/) | The attributes, the interfaces, and the `AddModule` methods. |
 | [DependencyModules.SourceGenerator](https://www.nuget.org/packages/DependencyModules.SourceGenerator/) | The source generator. It operates only when you compile. |
-| [DependencyModules.xUnit](https://www.nuget.org/packages/DependencyModules.xUnit/) | `[ModuleTest]` for xUnit v3. |
+| [DependencyModules.xUnit](https://www.nuget.org/packages/DependencyModules.xUnit/) | `[ModuleTest]` for xUnit v3, with `xunit.v3` version 3. |
+| [DependencyModules.xUnit4](https://www.nuget.org/packages/DependencyModules.xUnit4/) | `[ModuleTest]` for xUnit v3, with `xunit.v3` version 4. |
 | [DependencyModules.NUnit](https://www.nuget.org/packages/DependencyModules.NUnit/) | `[ModuleTest]` and `[ModuleTestCase]` for NUnit 4. |
-| [DependencyModules.Testing](https://www.nuget.org/packages/DependencyModules.Testing/) | The test attributes and interfaces that the xUnit and NUnit packages use. |
+| [DependencyModules.Testing](https://www.nuget.org/packages/DependencyModules.Testing/) | The test attributes and interfaces that the xUnit and NUnit packages use. It also gives the test that runs, and a logger that writes to the output of the test. |
 | [DependencyModules.NSubstitute](https://www.nuget.org/packages/DependencyModules.NSubstitute/) | `[Mock]` parameters with NSubstitute. |
 | [DependencyModules.Moq](https://www.nuget.org/packages/DependencyModules.Moq/) | `[Mock]` and `Mock<T>` parameters with Moq. |
 | [DependencyModules.FakeItEasy](https://www.nuget.org/packages/DependencyModules.FakeItEasy/) | `[Mock]` parameters with FakeItEasy. |

integ-tests/SutProject.NUnitTests/CurrentTestTests.cs

@@ -0,0 +1,101 @@
+using DependencyModules.NUnit.Attributes;
+using DependencyModules.Testing.Attributes.Interfaces;
+using DependencyModules.Testing.Impl;
+using Microsoft.Extensions.Logging;
+using NUnit.Framework;
+using NUnit.Framework.Internal;
+
+namespace SutProject.NUnitTests;
+
+/// <summary>
+/// <c>CurrentTest</c> under NUnit, where the runner package answers from
+/// <c>TestExecutionContext.CurrentContext</c>.
+/// </summary>
+public class CurrentTestTests
+{
+    private static readonly List<object?> RepeatKeys = [];
+
+    [ModuleTest]
+    public void KeyIsNUnitsObjectForTheRunningTest() =>
+        Assert.That(CurrentTest.Key, Is.SameAs(TestExecutionContext.CurrentContext.CurrentTest));
+
+    [ModuleTest]
+    public void DisplayNameIsTheFullNameOfTheTest() =>
+        Assert.That(CurrentTest.DisplayName, Is.EqualTo(TestContext.CurrentContext.Test.FullName));
+
+    [ModuleTest]
+    public void AssemblyIsTheAssemblyOfTheTestClass() =>
+        Assert.That(CurrentTest.Assembly, Is.SameAs(typeof(CurrentTestTests).Assembly));
+
+    [ModuleTest]
+    public void ALineIsWrittenToTheOutputOfTheTest()
+    {
+        Assert.That(CurrentTest.TryWriteLine("written through CurrentTest"), Is.True);
+
+        Assert.That(
+            TestExecutionContext.CurrentContext.CurrentResult.Output,
+            Does.Contain("written through CurrentTest")
+        );
+    }
+
+    [ModuleTest]
+    public void TheLoggerProviderWritesToTheOutputOfTheTest()
+    {
+        new TestOutputLoggerProvider()
+            .CreateLogger("Shop.OrderService")
+            .LogInformation("Order {Id} accepted", 42);
+
+        Assert.That(
+            TestExecutionContext.CurrentContext.CurrentResult.Output,
+            Does.Contain("info: Shop.OrderService[0] Order 42 accepted")
+        );
+    }
+
+    /// <summary>
+    /// The container is built inside the iteration, so the test is already running in the hooks
+    /// that build it. Under xUnit it is not; the documentation of CurrentTest gives both.
+    /// </summary>
+    [ModuleTest]
+    [RecordCurrentTestAtStartup]
+    public void TheTestIsRunningWhileTheContainerIsBuilt()
+    {
+        Assert.That(RecordCurrentTestAtStartupAttribute.Key, Is.SameAs(CurrentTest.Key));
+        Assert.That(
+            TestExecutionContext.CurrentContext.CurrentResult.Output,
+            Does.Contain("written while the container is built")
+        );
+    }
+
+    /// <summary>
+    /// NUnit makes no object of its own for one iteration, so the key is the test's for all of
+    /// them. The documentation of CurrentTest says so; the container is still one per iteration.
+    /// </summary>
+    [ModuleTest]
+    [Repeat(2)]
+    public void TheIterationsOfARepeatedTestShareOneKey()
+    {
+        RepeatKeys.Add(CurrentTest.Key);
+
+        Assert.That(CurrentTest.Key, Is.Not.Null);
+        Assert.That(
+            RepeatKeys,
+            Has.Count.EqualTo(TestExecutionContext.CurrentContext.CurrentRepeatCount + 1)
+        );
+        Assert.That(RepeatKeys, Is.All.SameAs(RepeatKeys[0]));
+    }
+}
+
+[AttributeUsage(AttributeTargets.Method)]
+public sealed class RecordCurrentTestAtStartupAttribute : Attribute, ITestStartupAttribute
+{
+    public static object? Key { get; private set; }
+
+    public Task StartupAsync(ITestMethodContext testMethod, IServiceProvider serviceProvider)
+    {
+        Key = CurrentTest.Key;
+
+        CurrentTest.TryWriteLine("written while the container is built");
+
+        return Task.CompletedTask;
+    }
+}

integ-tests/SutProject.Tests/SutProject.Tests.csproj

@@ -12,7 +12,7 @@
         <ProjectReference Include="..\..\src\DependencyModules.NSubstitute\DependencyModules.NSubstitute.csproj" />
         <ProjectReference Include="..\..\src\DependencyModules.Moq\DependencyModules.Moq.csproj" />
         <ProjectReference Include="..\..\src\DependencyModules.FakeItEasy\DependencyModules.FakeItEasy.csproj" />
-        <ProjectReference Include="..\..\src\DependencyModules.xUnit\DependencyModules.xUnit.csproj" />
+        <ProjectReference Include="..\..\src\$(DependencyModulesXunitProject)\$(DependencyModulesXunitProject).csproj"/>
         <ProjectReference Include="..\SecondarySutProject\SecondarySutProject.csproj"/>
         <ProjectReference Include="..\SutProject\SutProject.csproj"/>
         <ProjectReference Include="..\..\src\DependencyModules.SourceGenerator\DependencyModules.SourceGenerator.csproj" OutputItemType="Analyzer" ReferenceOutputAssembly="false"/>
@@ -24,11 +24,12 @@
             <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
         </PackageReference>
         <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.12.0"/>
-        <PackageReference Include="xunit.runner.visualstudio" Version="3.1.5">
+        <PackageReference Include="xunit.runner.visualstudio" Version="$(XunitRunnerVersion)">
             <PrivateAssets>all</PrivateAssets>
             <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
         </PackageReference>
-        <PackageReference Include="xunit.v3" Version="3.2.2"/>
+        <!-- XunitMajor in Directory.Build.props selects the xunit.v3 major and the DependencyModules project. -->
+        <PackageReference Include="$(XunitV3Package)" Version="$(XunitV3Version)"/>
     </ItemGroup>
 
 </Project>