TUnit

Author: KSemenenko

.github/copilot-instructions.md

@@ -38,26 +38,23 @@ dotnet test
 
 ## Testing
 
-* We use xUnit for tests with FluentAssertions for assertions.
+* We use TUnit on Microsoft.Testing.Platform with Shouldly for assertions.
 * Do not emit "Arrange", "Act" or "Assert" comments.
 * Use the naming pattern: `Method_Scenario_ExpectedResult()`.
 * Copy existing style in nearby test files for method names and capitalization.
 
 ```csharp
-[Fact]
+[Test]
 public void Succeed_ShouldCreateSuccessfulResult()
 {
     var result = Result.Succeed();
 
     result.IsSuccess
-        .Should()
-        .BeTrue();
+        .ShouldBeTrue();
     result.IsFailed
-        .Should()
-        .BeFalse();
+        .ShouldBeFalse();
     result.Problem
-        .Should()
-        .BeNull();
+        .ShouldBeNull();
 }
 ```
 
@@ -143,4 +140,4 @@ if (result.IsFailed)
 **Performance:**
 * `Result` and `Result<T>` are structs - avoid boxing
 * Use railway-oriented programming to avoid intermediate variables
-* Cache common Problem instances for frequent errors
+* Cache common Problem instances for frequent errors

.github/workflows/ci.yml

@@ -30,7 +30,14 @@ jobs:
       run: dotnet build --configuration Release --no-restore
 
     - name: Test
-      run: dotnet test --configuration Release --no-build --verbosity normal --collect:"XPlat Code Coverage"
+      run: >-
+        dotnet test --solution ManagedCode.Communication.slnx
+        --configuration Release
+        --no-build
+        --coverage
+        --coverage-output coverage.cobertura.xml
+        --coverage-output-format cobertura
+        --output Normal
 
     - name: Upload coverage reports to Codecov
       uses: codecov/codecov-action@v7

.github/workflows/release.yml

@@ -39,7 +39,11 @@ jobs:
       run: dotnet build --configuration Release --no-restore
 
     - name: Test
-      run: dotnet test --configuration Release --no-build --verbosity normal
+      run: >-
+        dotnet test --solution ManagedCode.Communication.slnx
+        --configuration Release
+        --no-build
+        --output Normal
 
     - name: Pack NuGet packages
       run: dotnet pack --configuration Release --no-build --output ./artifacts

AGENTS.md

@@ -10,6 +10,7 @@ If I tell you to remember something, you do the same, update
 
 ## Rules to follow
 always check all test are passed.
+- Use TUnit with Microsoft.Testing.Platform for all .NET tests; do not add or retain xUnit packages, attributes, fixtures, configuration, or documentation.
 - Prefer static interface members for result/command factories to centralize shared overloads and avoid duplication across result-like types.
 - Use `DateTime.UtcNow` (never `DateTimeOffset`) for all timestamps; we assume every stored time is in UTC.
 - For `MergeAll`/`CombineAll` scenarios with mixed failures, keep aggregated behavior and preserve original errors in `Problem.Extensions` (do not flatten everything into validation-only output).
@@ -41,15 +42,15 @@ The solution `ManagedCode.Communication.slnx` ties together the core library (`M
 ## Build, Test, and Development Commands
 - `dotnet restore ManagedCode.Communication.slnx` – restore all project dependencies.
 - `dotnet build -c Release ManagedCode.Communication.slnx` – compile every project with warnings treated as errors.
-- `dotnet test ManagedCode.Communication.Tests/ManagedCode.Communication.Tests.csproj` – run the xUnit suite; produces `*.trx` logs under `ManagedCode.Communication.Tests`.
-- `dotnet test ManagedCode.Communication.Tests/ManagedCode.Communication.Tests.csproj /p:CollectCoverage=true /p:CoverletOutputFormat=lcov` – refresh `coverage.info` via coverlet.
+- `dotnet test --project ManagedCode.Communication.Tests/ManagedCode.Communication.Tests.csproj` – run the complete TUnit suite on Microsoft.Testing.Platform.
+- `dotnet test --project ManagedCode.Communication.Tests/ManagedCode.Communication.Tests.csproj --coverage --coverage-output-format cobertura` – collect coverage through Microsoft.Testing.Platform.
 - `dotnet run -c Release --project ManagedCode.Communication.Benchmark` – execute benchmark scenarios before performance-sensitive changes.
 
 ## Coding Style & Naming Conventions
 Formatting is driven by the root `.editorconfig`: spaces only, 4-space indent for C#, CRLF endings for code, braces on new lines, and explicit types except when the type is obvious. The repo builds with C# 13, nullable reference types enabled, and analyzers elevated to errors—leave no compiler warnings behind. Stick to domain-centric names (e.g., `ResultExtensionsTests`) and prefer PascalCase for members and const fields per the configured naming rules.
 
 ## Testing Guidelines
-All automated tests use xUnit with Shouldly and Microsoft test hosts; follow the existing spec style (`MethodUnderTest_WithScenario_ShouldOutcome`). New fixtures belong in the matching feature folder and should assert both success and failure branches for Result types. Maintain the default coverage settings supplied by `coverlet.collector`; update snapshots or helper helpers under `TestHelpers` (including shared Shouldly extensions) when shared setup changes.
+All automated tests use TUnit with Shouldly on Microsoft.Testing.Platform; follow the existing spec style (`MethodUnderTest_WithScenario_ShouldOutcome`). New fixtures belong in the matching feature folder and should assert both success and failure branches for Result types. Use TUnit data sources and lifecycle hooks, collect coverage through `Microsoft.Testing.Extensions.CodeCoverage`, and update shared helpers under `TestHelpers` when shared setup changes.
 
 ## Commit & Pull Request Guidelines
 Commits in this repository stay short, imperative, and often reference the related issue or PR number (e.g., `Add FailBadRequest methods (#30)`). Mirror that tone, limit each commit to a coherent change, and include updates to docs or benchmarks when behavior shifts. Pull requests should summarize intent, list breaking changes, attach relevant `dotnet test` outputs or coverage deltas, and link tracked issues. Screenshots or sample payloads are welcome for HTTP-facing work.

ManagedCode.Communication.Tests/AspNetCore/Extensions/CommandCleanupBackgroundServiceIntegrationTests.cs

@@ -1,5 +1,5 @@
-using System.Collections.Generic;
 using System;
+using System.Collections.Generic;
 using System.Linq;
 using System.Threading.Tasks;
 using ManagedCode.Communication;
@@ -10,13 +10,12 @@
 using Microsoft.AspNetCore.TestHost;
 using Microsoft.Extensions.DependencyInjection;
 using Shouldly;
-using Xunit;
 
 namespace ManagedCode.Communication.Tests.AspNetCore.Extensions;
 
 public class CommandCleanupBackgroundServiceIntegrationTests
 {
-    [Fact]
+    [Test]
     public async Task CommandCleanupBackgroundService_PerformsCleanupAndHealthLogging()
     {
         var store = new TrackingCleanupStore();
@@ -38,7 +37,7 @@ public async Task CommandCleanupBackgroundService_PerformsCleanupAndHealthLoggin
         await app.StopAsync();
     }
 
-    [Fact]
+    [Test]
     public async Task CommandCleanupBackgroundService_ContinuesAfterCleanupFailure()
     {
         var store = new TrackingCleanupStore(throwOnFirstCompletedCleanup: true);

ManagedCode.Communication.Tests/AspNetCore/Extensions/CommandCleanupExtensionsTests.cs

@@ -5,13 +5,12 @@
 using ManagedCode.Communication.AspNetCore.Extensions;
 using ManagedCode.Communication.Commands;
 using Shouldly;
-using Xunit;
 
 namespace ManagedCode.Communication.Tests.AspNetCore.Extensions;
 
 public class CommandCleanupExtensionsTests
 {
-    [Fact]
+    [Test]
     public async Task AutoCleanupAsync_UsesDefaultAgesAndAggregatesResults()
     {
         var store = new TrackingCommandIdempotencyStore
@@ -33,7 +32,7 @@ public async Task AutoCleanupAsync_UsesDefaultAgesAndAggregatesResults()
         store.CleanupCalls[2].MaxAge.ShouldBe(TimeSpan.FromMinutes(30));
     }
 
-    [Fact]
+    [Test]
     public async Task GetHealthMetricsAsync_ReturnsCommandCountsAndRatios()
     {
         var store = new TrackingCommandIdempotencyStore
@@ -58,7 +57,7 @@ public async Task GetHealthMetricsAsync_ReturnsCommandCountsAndRatios()
         metrics.FailureRate.ShouldBe(10);
     }
 
-    [Fact]
+    [Test]
     public async Task GetHealthMetricsAsync_WhenNoCommands_ReturnsZeroRates()
     {
         var store = new TrackingCommandIdempotencyStore

ManagedCode.Communication.Tests/AspNetCore/Extensions/CommandIdempotencyExtensionsTests.cs

@@ -6,13 +6,12 @@
 using ManagedCode.Communication.Commands;
 using ManagedCode.Communication.Commands.Extensions;
 using Shouldly;
-using Xunit;
 
 namespace ManagedCode.Communication.Tests.AspNetCore.Extensions;
 
 public class CommandIdempotencyExtensionsTests
 {
-    [Fact]
+    [Test]
     public async Task ExecuteIdempotentAsync_ReturnsCompletedResultWithoutExecuting()
     {
         var store = new TestCommandIdempotencyStoreSimulator();
@@ -34,7 +33,7 @@ public async Task ExecuteIdempotentAsync_ReturnsCompletedResultWithoutExecuting(
         store.SetCommandResultCalls.ShouldBe(0);
     }
 
-    [Fact]
+    [Test]
     public async Task ExecuteIdempotentAsync_ExecutesWhenNotFoundAndPersistsResult()
     {
         var store = new TestCommandIdempotencyStoreSimulator();
@@ -56,7 +55,7 @@ public async Task ExecuteIdempotentAsync_ExecutesWhenNotFoundAndPersistsResult()
         ((string?)store.GetResult("cmd-run")).ShouldBe("executed");
     }
 
-    [Fact]
+    [Test]
     public async Task ExecuteIdempotentAsync_WhenExecutionFails_MarksFailedAndRethrows()
     {
         var store = new TestCommandIdempotencyStoreSimulator();
@@ -73,7 +72,7 @@ await ManagedCode.Communication.Commands.Extensions.CommandIdempotencyExtensions
         store.GetStatus("cmd-fail").ShouldBe(CommandExecutionStatus.Failed);
     }
 
-    [Fact]
+    [Test]
     public async Task ExecuteIdempotentAsync_WhenInProgressWaitsUntilCompleted()
     {
         var store = new TestCommandIdempotencyStoreSimulator();
@@ -93,7 +92,7 @@ public async Task ExecuteIdempotentAsync_WhenInProgressWaitsUntilCompleted()
         store.GetCommandResultCalls.ShouldBe(1);
     }
 
-    [Fact]
+    [Test]
     public async Task ExecuteIdempotentWithRetryAsync_RetriesAfterFailureAndReturnsResult()
     {
         var store = new TestCommandIdempotencyStoreSimulator();
@@ -121,7 +120,7 @@ public async Task ExecuteIdempotentWithRetryAsync_RetriesAfterFailureAndReturnsR
         store.GetStatus("cmd-retry").ShouldBe(CommandExecutionStatus.Completed);
     }
 
-    [Fact]
+    [Test]
     public async Task ExecuteBatchIdempotentAsync_ReturnsCachedResultsAndExecutesPending()
     {
         var store = new TestCommandIdempotencyStoreSimulator();
@@ -145,7 +144,7 @@ public async Task ExecuteBatchIdempotentAsync_ReturnsCachedResultsAndExecutesPen
         store.GetCommandResultCalls.ShouldBe(0);
     }
 
-    [Fact]
+    [Test]
     public async Task TryGetCachedResultAsync_WhenCompleted_ReturnsValue()
     {
         var store = new TestCommandIdempotencyStoreSimulator();
@@ -160,7 +159,7 @@ public async Task TryGetCachedResultAsync_WhenCompleted_ReturnsValue()
         result.ShouldBe("done");
     }
 
-    [Fact]
+    [Test]
     public async Task TryGetCachedResultAsync_WhenNotCompleted_ReturnsEmpty()
     {
         var store = new TestCommandIdempotencyStoreSimulator();
@@ -173,7 +172,7 @@ public async Task TryGetCachedResultAsync_WhenNotCompleted_ReturnsEmpty()
         result.ShouldBeNull();
     }
 
-    [Fact]
+    [Test]
     public async Task ExecuteWithTimeoutAsync_ReturnsResultWhenWithinTimeout()
     {
         var store = new TestCommandIdempotencyStoreSimulator();
@@ -191,7 +190,7 @@ public async Task ExecuteWithTimeoutAsync_ReturnsResultWhenWithinTimeout()
         result.ShouldBe("quick");
     }
 
-    [Fact]
+    [Test]
     public async Task ExecuteBatchIdempotentAsync_AllCompletedResults_DoNotExecutePendingOperations()
     {
         var store = new TestCommandIdempotencyStoreSimulator();
@@ -226,7 +225,7 @@ public async Task ExecuteBatchIdempotentAsync_AllCompletedResults_DoNotExecutePe
         store.SetCommandResultCalls.ShouldBe(0);
     }
 
-    [Fact]
+    [Test]
     public async Task ExecuteIdempotentAsync_WhenWaitForCompletionHitsFailed_Throws()
     {
         var store = new TestCommandIdempotencyStoreSimulator();
@@ -239,7 +238,7 @@ await ManagedCode.Communication.Commands.Extensions.CommandIdempotencyExtensions
                 () => Task.FromResult("should-not-run")));
     }
 
-    [Fact]
+    [Test]
     public async Task ExecuteIdempotentAsync_WhenWaitForCompletionHitsNotFound_Throws()
     {
         var store = new TestCommandIdempotencyStoreSimulator();
@@ -252,7 +251,7 @@ await ManagedCode.Communication.Commands.Extensions.CommandIdempotencyExtensions
                 () => Task.FromResult("should-not-run")));
     }
 
-    [Fact]
+    [Test]
     public async Task ExecuteIdempotentWithRetryAsync_WhenMaxRetriesExceeded_ThrowsLastException()
     {
         var store = new TestCommandIdempotencyStoreSimulator();
@@ -274,7 +273,7 @@ public async Task ExecuteIdempotentWithRetryAsync_WhenMaxRetriesExceeded_ThrowsL
         exception.Message.ShouldBe("attempt-2");
     }
 
-    [Fact]
+    [Test]
     public async Task ExecuteIdempotentWithRetryAsync_CancelledToken_StopsWithoutExecutingOperation()
     {
         var store = new TestCommandIdempotencyStoreSimulator();

ManagedCode.Communication.Tests/AspNetCore/Extensions/CommandIdempotencyServiceCollectionExtensionsTests.cs

@@ -5,13 +5,12 @@
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Hosting;
 using Shouldly;
-using Xunit;
 
 namespace ManagedCode.Communication.Tests.AspNetCore.Extensions;
 
 public class CommandIdempotencyServiceCollectionExtensionsTests
 {
-    [Fact]
+    [Test]
     public void AddCommandIdempotency_RegistersStoreAndBackgroundCleanup()
     {
         var services = new ServiceCollection();
@@ -38,7 +37,7 @@ public void AddCommandIdempotency_RegistersStoreAndBackgroundCleanup()
         hosted.Count.ShouldBe(1);
     }
 
-    [Fact]
+    [Test]
     public void AddCommandIdempotency_WithInstance_RegistersSameStoreInstance()
     {
         var services = new ServiceCollection();
@@ -56,7 +55,7 @@ public void AddCommandIdempotency_WithInstance_RegistersSameStoreInstance()
         hosted.Count.ShouldBe(1);
     }
 
-    [Fact]
+    [Test]
     public void AddCommandIdempotencyStore_DoesNotRegisterBackgroundCleanup()
     {
         var services = new ServiceCollection();
@@ -72,7 +71,7 @@ public void AddCommandIdempotencyStore_DoesNotRegisterBackgroundCleanup()
         hosted.ShouldBeEmpty();
     }
 
-    [Fact]
+    [Test]
     public void AddCommandIdempotencyWithManualCleanup_DoesNotRegisterHostedServiceAndPreservesOptions()
     {
         var services = new ServiceCollection();