Add file-resolution and caret-based lookup tests verifying which handler file Go to Handler resolves for a MediatR request

.gitignore

@@ -31,3 +31,5 @@ _dotTrace*
 
 # NuGet tools
 .nuget/
+
+**/TestResult.xml

CHANGELOG.md

@@ -1,7 +1,7 @@
 # Changelog
 All notable changes to this project will be documented in this file.
 
-## 26.09.04XX
+## 26.09.19XX
 - "Go to Handler" now also works with the caret anywhere inside a `mediator.Send(...)` /
   `Publish(...)` call: the first argument's type is resolved, so there is no need to navigate to the
   request declaration first.

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

@@ -14,6 +14,13 @@ public static class TestSolutionFiles
 {
     private static readonly string TestSolutionPath = ResolveTestSolutionPath();
 
+    /// <summary>
+    /// Absolute path to the TestSolution folder, used to turn an on-disk file path (e.g. a
+    /// resolved handler's source file) back into the relative path form used elsewhere in these
+    /// tests (e.g. "MediatR/Handlers/GetEntityHandler.cs").
+    /// </summary>
+    public static string RootPath => TestSolutionPath;
+
     public static string[] MediatR { get; } = LibraryFiles("MediatR");
 
     public static string[] Mediator { get; } = LibraryFiles("Mediator");

src/dotnet/MediatorPlugin.Tests/LookupTestBase.cs

@@ -1,4 +1,5 @@
 using System.Collections.Generic;
+using System.IO;
 using System.Linq;
 using JetBrains.Lifetimes;
 using JetBrains.ProjectModel;
@@ -9,6 +10,7 @@
 using JetBrains.ReSharper.Resources.Shell;
 using JetBrains.ReSharper.TestFramework;
 using NUnit.Framework;
+using Octelys.MediatorPlugin.Tests.Infrastructure;
 using ReSharper.MediatorPlugin.Services.Libraries;
 
 namespace Octelys.MediatorPlugin.Tests;
@@ -23,6 +25,7 @@ public abstract class LookupTestBase : BaseTestWithSingleProject
 {
     private string _requestTypeName;
     private string[] _expectedHandlerNames;
+    private string[] _expectedHandlerFilePaths;
 
     protected override string RelativeTestDataPath => "TestSolution";
 
@@ -42,7 +45,18 @@ ISolution solution
         {
             IIdentifier requestIdentifier = FindDeclarationIdentifier(solution, _requestTypeName);
 
-            IEnumerable<ITypeElement> handlers = new LibraryAdaptor().FindHandlers(requestIdentifier);
+            ITypeElement[] handlers = new LibraryAdaptor().FindHandlers(requestIdentifier).ToArray();
+
+            if (_expectedHandlerFilePaths is not null)
+            {
+                string[] handlerFilePaths = handlers
+                    .SelectMany(GetRelativeFilePaths)
+                    .OrderBy(path => path)
+                    .ToArray();
+
+                Assert.That(handlerFilePaths, Is.EqualTo(_expectedHandlerFilePaths.OrderBy(path => path).ToArray()));
+                return;
+            }
 
             string[] handlerNames = handlers
                 .Select(handler => handler.ShortName)
@@ -66,10 +80,49 @@ params string[] fileNames
     {
         _requestTypeName = requestTypeName;
         _expectedHandlerNames = expectedHandlerNames;
+        _expectedHandlerFilePaths = null;
+
+        DoTestSolution(fileNames);
+    }
+
+    /// <summary>
+    /// Loads the given files as a test solution and asserts that the request or notification
+    /// resolves to handlers declared in exactly the expected files (relative to
+    /// test/data/TestSolution, e.g. "MediatR/Handlers/GetEntityHandler.cs") - i.e. the file(s)
+    /// "Go to Handler" would navigate to when the caret sits on the request. The lookup itself
+    /// runs in <see cref="DoTest" />.
+    /// </summary>
+    protected void AssertHandlerFilesFor
+    (
+        string requestTypeName,
+        string[] expectedHandlerFilePaths,
+        params string[] fileNames
+    )
+    {
+        _requestTypeName = requestTypeName;
+        _expectedHandlerNames = null;
+        _expectedHandlerFilePaths = expectedHandlerFilePaths;
 
         DoTestSolution(fileNames);
     }
 
+    /// <summary>
+    /// Resolves the on-disk file(s) declaring the given handler back to their path relative to
+    /// test/data/TestSolution, matching the relative path form used to load test files (e.g. via
+    /// <see cref="TestSolutionFiles" />).
+    /// </summary>
+    private static IEnumerable<string> GetRelativeFilePaths
+    (
+        ITypeElement handler
+    )
+    {
+        return handler
+            .GetSourceFiles()
+            .Select(sourceFile => sourceFile.GetLocation().FullPath)
+            .Select(fullPath => fullPath.Substring(TestSolutionFiles.RootPath.Length + 1))
+            .Select(relativePath => relativePath.Replace(Path.DirectorySeparatorChar, '/'));
+    }
+
     /// <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

src/dotnet/MediatorPlugin.Tests/MediatR.GoToHandler.CaretTests.V12.cs

@@ -0,0 +1,8 @@
+using Octelys.MediatorPlugin.Tests.Infrastructure;
+
+namespace Octelys.MediatorPlugin.Tests;
+
+[MediatRV12TestPackages]
+public sealed class MediatrGoToHandlerCaretTestsV12 : MediatrGoToHandlerCaretTestsBase
+{
+}

src/dotnet/MediatorPlugin.Tests/MediatR.GoToHandler.CaretTests.V13.cs

@@ -0,0 +1,8 @@
+using Octelys.MediatorPlugin.Tests.Infrastructure;
+
+namespace Octelys.MediatorPlugin.Tests;
+
+[MediatRV13TestPackages]
+public sealed class MediatrGoToHandlerCaretTestsV13 : MediatrGoToHandlerCaretTestsBase
+{
+}

src/dotnet/MediatorPlugin.Tests/MediatR.GoToHandler.CaretTests.V14.cs

@@ -0,0 +1,8 @@
+using Octelys.MediatorPlugin.Tests.Infrastructure;
+
+namespace Octelys.MediatorPlugin.Tests;
+
+[MediatRV14TestPackages]
+public sealed class MediatrGoToHandlerCaretTestsV14 : MediatrGoToHandlerCaretTestsBase
+{
+}

src/dotnet/MediatorPlugin.Tests/MediatR.GoToHandler.CaretTests.cs

@@ -0,0 +1,84 @@
+using System.IO;
+using System.Linq;
+using JetBrains.Lifetimes;
+using JetBrains.ProjectModel;
+using JetBrains.ReSharper.Feature.Services.Util;
+using JetBrains.ReSharper.Psi;
+using JetBrains.ReSharper.Psi.Tree;
+using JetBrains.ReSharper.Resources.Shell;
+using JetBrains.ReSharper.TestFramework;
+using JetBrains.TextControl;
+using NUnit.Framework;
+using ReSharper.MediatorPlugin.Services.Libraries;
+
+namespace Octelys.MediatorPlugin.Tests;
+
+/// <summary>
+/// Positions a real caret (via the "{caret}" marker in each test's data file) and asserts which
+/// handler file the plugin resolves, if any, for the identifier under it. Unlike <see cref="LookupTestBase" />,
+/// which locates the request's declaration identifier directly through the PSI, this test goes
+/// through the same caret-to-PSI resolution (<see cref="TextControlToPsi" />) that the plugin's
+/// own actions use (e.g. GoToHandlerAction.GetSelectedMediatrRequest), so it exercises the literal
+/// "caret sits on this token" scenario rather than simulating it by name. <see cref="CaretInNamespace" />
+/// and <see cref="CaretOnSendCall" /> place the caret on identifiers that are not a Mediator request
+/// declaration and assert that no handler is resolved.
+/// </summary>
+[TestNetCoreLatest]
+[TestReferences("System.Runtime")]
+public abstract class MediatrGoToHandlerCaretTestsBase : BaseTestWithTextControl
+{
+    private static readonly string[] TestsExpectingNoHandler =
+    {
+        nameof(CaretInNamespace),
+        nameof(CaretOnSendCall)
+    };
+
+    protected override string RelativeTestDataPath => "GoToHandlerCaretTests";
+
+    [Test]
+    public void Request() => DoNamedTest("Handler.cs");
+
+    [Test]
+    public void RequestCaretAtBeginning() => DoNamedTest("Handler.cs");
+
+    [Test]
+    public void CaretInNamespace() => DoNamedTest("Handler.cs");
+
+    [Test]
+    public void CaretOnSendCall() => DoNamedTest("Handler.cs");
+
+    protected override void DoTest
+    (
+        Lifetime lifetime,
+        ISolution solution
+    )
+    {
+        solution.GetPsiServices().Files.CommitAllDocuments();
+
+        using (ReadLockCookie.Create())
+        {
+            ITextControl textControl = OpenTextControl(lifetime, GetCaretPosition());
+
+            IIdentifier requestIdentifier = TextControlToPsi.GetElement<IIdentifier>(solution, textControl);
+
+            Assert.That(requestIdentifier, Is.Not.Null, "No identifier was found at the caret.");
+
+            ITypeElement[] handlers = new LibraryAdaptor().FindHandlers(requestIdentifier).ToArray();
+
+            if (TestsExpectingNoHandler.Contains(TestMethodName))
+            {
+                Assert.That(handlers, Is.Empty, "Expected no handler to be resolved from this caret position.");
+
+                return;
+            }
+
+            string handlerFileName = handlers
+                .Single()
+                .GetSourceFiles()
+                .Select(sourceFile => Path.GetFileName(sourceFile.GetLocation().FullPath))
+                .Single();
+
+            Assert.That(handlerFileName, Is.EqualTo("Handler.cs"));
+        }
+    }
+}

src/dotnet/MediatorPlugin.Tests/MediatR.Requests.Tests.cs

@@ -115,4 +115,16 @@ public void FindHandlers_HandlerImplementsSharedGenericHandlerInterface_HandlerR
             TestSolutionFiles.MediatR
         );
     }
+
+    [Test]
+    public void FindHandlers_CaretOnRequest_HandlerFileReturned()
+    {
+        //  Act & Assert.
+        AssertHandlerFilesFor
+        (
+            "Domain.GetEntityRequest",
+            ["MediatR/Handlers/GetEntityHandler.cs"],
+            TestSolutionFiles.MediatR
+        );
+    }
 }

src/dotnet/MediatorPlugin.Tests/MediatorPlugin.Tests.csproj

@@ -52,6 +52,15 @@
         <Compile Update="Mediator.Requests.V3.Tests.cs">
           <DependentUpon>Mediator.Requests.Tests.cs</DependentUpon>
         </Compile>
+        <Compile Update="MediatR.GoToHandler.CaretTests.V12.cs">
+          <DependentUpon>MediatR.GoToHandler.CaretTests.cs</DependentUpon>
+        </Compile>
+        <Compile Update="MediatR.GoToHandler.CaretTests.V13.cs">
+          <DependentUpon>MediatR.GoToHandler.CaretTests.cs</DependentUpon>
+        </Compile>
+        <Compile Update="MediatR.GoToHandler.CaretTests.V14.cs">
+          <DependentUpon>MediatR.GoToHandler.CaretTests.cs</DependentUpon>
+        </Compile>
     </ItemGroup>
 
     <ItemGroup>

src/dotnet/MediatorPlugin.Tests/test/data/GoToHandlerCaretTests/CaretInNamespace.cs

@@ -0,0 +1,7 @@
+using MediatR;
+
+namespace {caret}Domain;
+
+public class GetEntityRequest : IRequest<string>
+{
+}

src/dotnet/MediatorPlugin.Tests/test/data/GoToHandlerCaretTests/CaretOnSendCall.cs

@@ -0,0 +1,24 @@
+using System.Threading;
+using System.Threading.Tasks;
+using MediatR;
+
+namespace Domain;
+
+public class GetEntityRequest : IRequest<string>
+{
+}
+
+public class GetEntityRequestSender
+{
+    private readonly IMediator _mediator;
+
+    public GetEntityRequestSender(IMediator mediator)
+    {
+        _mediator = mediator;
+    }
+
+    public Task<string> SendAsync(CancellationToken cancellationToken)
+    {
+        return _mediator.{caret}Send(new GetEntityRequest(), cancellationToken);
+    }
+}

src/dotnet/MediatorPlugin.Tests/test/data/GoToHandlerCaretTests/Handler.cs

@@ -0,0 +1,14 @@
+using System.Threading;
+using System.Threading.Tasks;
+using Domain;
+using MediatR;
+
+namespace Application;
+
+internal sealed class GetEntityRequestHandler : IRequestHandler<GetEntityRequest, string>
+{
+    public Task<string> Handle(GetEntityRequest request, CancellationToken cancellationToken)
+    {
+        throw new System.NotImplementedException();
+    }
+}

src/dotnet/MediatorPlugin.Tests/test/data/GoToHandlerCaretTests/Request.cs

@@ -0,0 +1,7 @@
+using MediatR;
+
+namespace Domain;
+
+public class GetEntity{caret}Request : IRequest<string>
+{
+}

src/dotnet/MediatorPlugin.Tests/test/data/GoToHandlerCaretTests/RequestCaretAtBeginning.cs

@@ -0,0 +1,7 @@
+using MediatR;
+
+namespace Domain;
+
+public class {caret}GetEntityRequest : IRequest<string>
+{
+}

test-solution/DotNetCore6Project/MediatR/MediatRCallsite.cs

@@ -0,0 +1,19 @@
+using DotNetCore6_Domain.MediatR.Requests;
+using MediatR;
+
+namespace DotNetCore6_Domain.MediatR;
+
+public class MediatRCallsite
+{
+    private readonly IMediator _mediator;
+
+    public MediatRCallsite(IMediator mediator)
+    {
+        _mediator = mediator;
+    }
+
+    public async Task RunAsync(CancellationToken cancellationToken)
+    {
+        await _mediator.Send(new CustomClassRequest(), cancellationToken);
+    }
+}

test-solution/DotNetCore6Project/Mediator/MediatorCallsite.cs

@@ -0,0 +1,19 @@
+using DotNetCore6_Domain.Mediator.Requests;
+using MediatR;
+
+namespace DotNetCore6_Domain.Mediator;
+
+public class MediatorCallsite
+{
+    private readonly IMediator _mediator;
+
+    public MediatorCallsite(IMediator mediator)
+    {
+        _mediator = mediator;
+    }
+
+    public async Task RunAsync(CancellationToken cancellationToken)
+    {
+        await _mediator.Send(new NewMediatorRequest(), cancellationToken);
+    }
+}