test: add SDK-level tests resolving MediatR handlers from a request against a real headless solution and PSI

.github/workflows/cicd.yml

@@ -19,6 +19,51 @@ on:
         description: 'Runner'
 
 jobs:
+  test:
+    name: test (dotnet)
+    # The ReSharper test framework targets net472 and needs the .NET Framework
+    # runtime, so these tests cannot run on the ubuntu runner used by `build`.
+    runs-on: windows-latest
+    timeout-minutes: 30
+    steps:
+      - name: checkout
+        uses: actions/checkout@v7
+
+      - name: install .NET SDK
+        uses: actions/setup-dotnet@v6
+        with:
+          dotnet-version: '9.x'
+
+      # The ReSharper SDK drops its own NUnit3.TestAdapter.dll into the output
+      # directory and it cannot be loaded by VSTest, shadowing the working one
+      # from the NUnit3TestAdapter package. Point VSTest straight at the latter.
+      - name: restore
+        run: dotnet restore src/dotnet/MediatorPlugin.Tests/MediatorPlugin.Tests.csproj
+
+      - name: test
+        shell: pwsh
+        run: |
+          $packages = if ($env:NUGET_PACKAGES) { $env:NUGET_PACKAGES } else { Join-Path $env:USERPROFILE ".nuget\packages" }
+          $adapter = Join-Path $packages "nunit3testadapter\4.6.0\build\net462"
+          if (-not (Test-Path $adapter)) { throw "NUnit adapter not found at $adapter" }
+          dotnet test src/dotnet/MediatorPlugin.Tests/MediatorPlugin.Tests.csproj `
+            --test-adapter-path $adapter `
+            --logger GitHubActions `
+            --logger "trx;LogFileName=results.trx" `
+            --no-restore `
+            --results-directory "${{ github.workspace }}/testresults"
+
+      # VSTest exits 0 when it discovers nothing, so a broken adapter would
+      # otherwise report a green build that ran no tests at all.
+      - name: assert tests actually ran
+        shell: pwsh
+        run: |
+          $trx = Get-ChildItem "${{ github.workspace }}/testresults" -Filter *.trx -Recurse | Select-Object -First 1
+          if (-not $trx) { throw "No .trx produced - the test run did not happen." }
+          $counters = ([xml](Get-Content $trx.FullName)).TestRun.ResultSummary.Counters
+          Write-Host "total=$($counters.total) executed=$($counters.executed) passed=$($counters.passed) failed=$($counters.failed)"
+          if ([int]$counters.executed -lt 1) { throw "No tests were executed." }
+
   build:
     runs-on: ${{ inputs.runs_on || 'ubuntu-latest' }}
     steps:

AGENTS.md

@@ -0,0 +1,41 @@
+# AGENTS.md
+
+ReSharper + Rider plugin for MediatR/mediator codebases. Two halves that ship together:
+a .NET backend (`src/dotnet`) and a Kotlin/IntelliJ frontend (`src/rider`), wired over a
+generated protocol (`protocol/`).
+
+## Layout
+
+| Path | What it is |
+| --- | --- |
+| `src/dotnet/MediatorPlugin` | Backend: actions, navigations, diagnostics, services |
+| `src/dotnet/MediatorPlugin.Tests` | Backend tests (ReSharper test framework) |
+| `src/rider/main` | Kotlin frontend + `META-INF/plugin.xml` |
+| `protocol` | RD protocol model shared by both halves |
+| `test-solution` | Sample solution the tests and manual runs operate on |
+
+## Build and test
+
+```bash
+dotnet test src/dotnet/MediatorPlugin.Tests/MediatorPlugin.Tests.csproj
+./gradlew :prepareSandbox -PPluginVersion=<version>   # full plugin build
+```
+
+- **Everything targets `net472`.** The ReSharper test framework needs the .NET Framework
+  runtime, so the backend tests only run on Windows — CI runs them on `windows-latest`
+  while the Gradle build runs on Ubuntu. Don't "fix" a test failure that is really a
+  platform mismatch.
+- `MediatorPlugin` has **two project files** in the same directory:
+  `MediatorPlugin.csproj` (ReSharper) and `MediatorPlugin.Rider.csproj` (Rider). A change
+  to one usually belongs in both; check before assuming a single build covers you.
+- `PluginVersion` in `gradle.properties` and the `<version>` in `plugin.xml` are
+  `_PLACEHOLDER_` on purpose. CI stamps them via `update-version.sh`. Never commit a
+  concrete version there.
+
+## File editing
+
+- Modify files with your editor/patch tools (str-replace, create-file, apply-patch).
+- Do not write files through the shell: no heredocs (`cat > file <<'EOF'`), no `echo >`,
+  `printf >`, `tee`, or `sed -i`. Shell redirection into tracked files is prohibited.
+- The shell is for read-only inspection (`cat`, `grep`, `ls`, `find`) and for running
+  builds, tests, and git commands.

src/dotnet/MediatorPlugin.Tests/Infrastructure/MediatRV12TestPackagesAttribute.cs

@@ -0,0 +1,10 @@
+using JetBrains.ReSharper.TestFramework;
+
+namespace Octelys.MediatorPlugin.Tests.Infrastructure;
+
+public sealed class MediatRV12TestPackagesAttribute : TestPackagesAttribute
+{
+    public MediatRV12TestPackagesAttribute() : base(Tests.Packages.MediatR.V12)
+    {
+    }
+}

src/dotnet/MediatorPlugin.Tests/Infrastructure/MediatRV13TestPackagesAttribute.cs

@@ -0,0 +1,10 @@
+using JetBrains.ReSharper.TestFramework;
+
+namespace Octelys.MediatorPlugin.Tests.Infrastructure;
+
+public sealed class MediatRV13TestPackagesAttribute : TestPackagesAttribute
+{
+    public MediatRV13TestPackagesAttribute() : base(Tests.Packages.MediatR.V13)
+    {
+    }
+}

src/dotnet/MediatorPlugin.Tests/Infrastructure/MediatRV14TestPackagesAttribute.cs

@@ -0,0 +1,10 @@
+using JetBrains.ReSharper.TestFramework;
+
+namespace Octelys.MediatorPlugin.Tests.Infrastructure;
+
+public sealed class MediatRV14TestPackagesAttribute : TestPackagesAttribute
+{
+    public MediatRV14TestPackagesAttribute() : base(Tests.Packages.MediatR.V14)
+    {
+    }
+}

src/dotnet/MediatorPlugin.Tests/Infrastructure/MediatorV3TestPackagesAttribute.cs

@@ -0,0 +1,10 @@
+using JetBrains.ReSharper.TestFramework;
+
+namespace Octelys.MediatorPlugin.Tests.Infrastructure;
+
+public sealed class MediatorV3TestPackagesAttribute : TestPackagesAttribute
+{
+    public MediatorV3TestPackagesAttribute() : base(Tests.Packages.Mediator.V3)
+    {
+    }
+}

src/dotnet/MediatorPlugin.Tests/Infrastructure/TestSolutionFiles.cs

@@ -0,0 +1,53 @@
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Runtime.CompilerServices;
+
+namespace Octelys.MediatorPlugin.Tests.Infrastructure;
+
+/// <summary>
+/// Enumerates every file under a library's folder in the shared TestSolution test data (plus the
+/// common Entities folder), so lookup tests can load the whole library instead of curating a file
+/// subset per test.
+/// </summary>
+public static class TestSolutionFiles
+{
+    private static readonly string TestSolutionPath = ResolveTestSolutionPath();
+
+    public static string[] MediatR { get; } = LibraryFiles("MediatR");
+
+    public static string[] Mediator { get; } = LibraryFiles("Mediator");
+
+    private static string[] LibraryFiles
+    (
+        string libraryFolderName
+    )
+    {
+        return new[] { libraryFolderName, "Entities" }
+            .SelectMany(EnumerateRelativeFiles)
+            .OrderBy(relativePath => relativePath)
+            .ToArray();
+    }
+
+    private static IEnumerable<string> EnumerateRelativeFiles
+    (
+        string folderName
+    )
+    {
+        string folderPath = Path.Combine(TestSolutionPath, folderName);
+
+        return Directory
+            .EnumerateFiles(folderPath, "*.cs", SearchOption.AllDirectories)
+            .Select(filePath => filePath.Substring(TestSolutionPath.Length + 1).Replace(Path.DirectorySeparatorChar, '/'));
+    }
+
+    private static string ResolveTestSolutionPath
+    (
+        [CallerFilePath] string sourceFilePath = ""
+    )
+    {
+        string projectPath = Path.GetDirectoryName(Path.GetDirectoryName(sourceFilePath));
+
+        return Path.Combine(projectPath!, "test", "data", "TestSolution");
+    }
+}

src/dotnet/MediatorPlugin.Tests/LookupTestBase.cs

@@ -0,0 +1,146 @@
+using System.Collections.Generic;
+using System.Linq;
+using JetBrains.Lifetimes;
+using JetBrains.ProjectModel;
+using JetBrains.ReSharper.Psi;
+using JetBrains.ReSharper.Psi.CSharp.Tree;
+using JetBrains.ReSharper.Psi.Files;
+using JetBrains.ReSharper.Psi.Tree;
+using JetBrains.ReSharper.Resources.Shell;
+using JetBrains.ReSharper.TestFramework;
+using NUnit.Framework;
+using ReSharper.MediatorPlugin.Services.Libraries;
+
+namespace Octelys.MediatorPlugin.Tests;
+
+/// <summary>
+/// Shared plumbing for tests that load a small test solution and assert which handlers the
+/// plugin resolves for a given request or notification type. Test data lives under
+/// test/data/TestSolution, organized per library (MediatR, Mediator) and kind (Requests,
+/// Notifications, Handlers, Entities).
+/// </summary>
+public abstract class LookupTestBase : BaseTestWithSingleProject
+{
+    private string _requestTypeName;
+    private string[] _expectedHandlerNames;
+
+    protected override string RelativeTestDataPath => "TestSolution";
+
+    /// <summary>
+    /// Runs inside the loaded test solution: the framework calls this once the project of the
+    /// current test has been restored and its PSI caches are ready.
+    /// </summary>
+    protected override void DoTest
+    (
+        Lifetime lifetime,
+        ISolution solution
+    )
+    {
+        solution.GetPsiServices().Files.CommitAllDocuments();
+
+        using (ReadLockCookie.Create())
+        {
+            IIdentifier requestIdentifier = FindDeclarationIdentifier(solution, _requestTypeName);
+
+            IEnumerable<ITypeElement> handlers = new LibraryAdaptor().FindHandlers(requestIdentifier);
+
+            string[] handlerNames = handlers
+                .Select(handler => handler.ShortName)
+                .OrderBy(name => name)
+                .ToArray();
+
+            Assert.That(handlerNames, Is.EqualTo(_expectedHandlerNames.OrderBy(name => name).ToArray()));
+        }
+    }
+
+    /// <summary>
+    /// Loads the given files as a test solution and asserts that the request or notification
+    /// resolves to exactly the expected handlers; the lookup itself runs in <see cref="DoTest" />.
+    /// </summary>
+    protected void AssertHandlersFor
+    (
+        string requestTypeName,
+        string[] expectedHandlerNames,
+        params string[] fileNames
+    )
+    {
+        _requestTypeName = requestTypeName;
+        _expectedHandlerNames = expectedHandlerNames;
+
+        DoTestSolution(fileNames);
+    }
+
+    /// <summary>
+    /// Returns the name token of the type declaration, which is the node the plugin receives
+    /// when the caret sits on a request in the editor. <paramref name="typeName" /> may be a
+    /// short name ("GetEntityRequest") when it is unique in the loaded files, or a fully
+    /// qualified name ("Domain.OtherNamespace.GetEntityRequest") to disambiguate types that
+    /// share a short name across namespaces.
+    /// </summary>
+    private static IIdentifier FindDeclarationIdentifier
+    (
+        ISolution solution,
+        string typeName
+    )
+    {
+        bool isQualified = typeName.Contains('.');
+
+        IIdentifier[] candidates = EnumerateIdentifiers(solution)
+            .Where(candidate => candidate.Parent is IClassLikeDeclaration)
+            .Where(candidate => isQualified ? GetFullName(candidate) == typeName : candidate.Name == typeName)
+            .ToArray();
+
+        Assert.That
+        (
+            candidates,
+            Has.Length.EqualTo(1),
+            candidates.Length == 0
+                ? $"No declaration of '{typeName}' was found in the test solution."
+                : $"Multiple declarations of '{typeName}' were found: {string.Join(", ", candidates.Select(GetFullName))}. " +
+                  "Qualify the name with its namespace to disambiguate."
+        );
+
+        return candidates[0];
+    }
+
+    private static string GetFullName
+    (
+        IIdentifier identifier
+    )
+    {
+        IClassLikeDeclaration declaration = (IClassLikeDeclaration)identifier.Parent;
+
+        return ((ITypeElement)declaration.DeclaredElement).GetClrName().FullName;
+    }
+
+    private static IEnumerable<IIdentifier> EnumerateIdentifiers
+    (
+        ISolution solution
+    )
+    {
+        foreach (IProject project in solution.GetAllProjects())
+        {
+            foreach (IProjectFile projectFile in project.GetAllProjectFiles(_ => true))
+            {
+                IPsiSourceFile sourceFile = projectFile.ToSourceFile();
+
+                if (sourceFile is null)
+                {
+                    continue;
+                }
+
+                IFile psiFile = sourceFile.GetPrimaryPsiFile();
+
+                if (psiFile is null)
+                {
+                    continue;
+                }
+
+                foreach (IIdentifier identifier in psiFile.Descendants<IIdentifier>().ToEnumerable())
+                {
+                    yield return identifier;
+                }
+            }
+        }
+    }
+}

src/dotnet/MediatorPlugin.Tests/MediatrCreateHandlrContextActionTests.cs → src/dotnet/MediatorPlugin.Tests/MediatR.CreateHandlR.Tests.cs

@@ -3,16 +3,15 @@
 using NUnit.Framework;
 using ReSharper.MediatorPlugin.Actions;
 
-namespace NoSuchCompany.MediatrPlugin.Tests;
+namespace Octelys.MediatorPlugin.Tests;
 
-[TestPackages("MediatR/12.1.0")]
 [TestReferences("System.Runtime")] // needed for IReadOnlyCollection type
-public class MediatrCreateHandlrContextActionTests : CSharpContextActionExecuteTestBase<CreateHandlrContextAction>
+public abstract class MediatRCreateHandlrContextActionTestsBase : CSharpContextActionExecuteTestBase<CreateHandlrContextAction>
 {
-    protected override string RelativeTestDataPath => nameof(MediatrCreateHandlrContextActionTests);
+    protected override string RelativeTestDataPath => "MediatrCreateHandlrContextActionTests";
 
     protected override string ExtraPath => "";
-    
+
     [Test, Order(0)] public void TestEnvironmentSetupCorrectly() => Assert.Pass();
     [Test] public void TestCommand() => DoNamedTest();
     [Test] public void TestSimpleQuery() => DoNamedTest();

src/dotnet/MediatorPlugin.Tests/MediatR.CreateHandlR.V12.Tests.cs

@@ -0,0 +1,8 @@
+using Octelys.MediatorPlugin.Tests.Infrastructure;
+
+namespace Octelys.MediatorPlugin.Tests;
+
+[MediatRV12TestPackages]
+public sealed class MediatRCreateHandlrContextActionTestsV12 : MediatRCreateHandlrContextActionTestsBase
+{
+}

src/dotnet/MediatorPlugin.Tests/MediatR.CreateHandlR.V13.Tests.cs

@@ -0,0 +1,8 @@
+using Octelys.MediatorPlugin.Tests.Infrastructure;
+
+namespace Octelys.MediatorPlugin.Tests;
+
+[MediatRV13TestPackages]
+public sealed class MediatRCreateHandlrContextActionTestsV13 : MediatRCreateHandlrContextActionTestsBase
+{
+}

src/dotnet/MediatorPlugin.Tests/MediatR.CreateHandlR.V14.Tests.cs

@@ -0,0 +1,8 @@
+using Octelys.MediatorPlugin.Tests.Infrastructure;
+
+namespace Octelys.MediatorPlugin.Tests;
+
+[MediatRV14TestPackages]
+public sealed class MediatRCreateHandlrContextActionTestsV14 : MediatRCreateHandlrContextActionTestsBase
+{
+}