Isolate test registration callback failures

src/TUnit.Engine/Services/TestFilterService.cs

@@ -113,6 +113,41 @@ private static TestRegisteredContext CreateTestRegisteredContext(TestContext tes
     }
 
     private async Task RegisterTest(AbstractExecutableTest test, bool isForExecution)
+    {
+        try
+        {
+            await RegisterTestCore(test, isForExecution).ConfigureAwait(false);
+        }
+        catch (Exception ex)
+        {
+            // Registration callbacks are user code. Preserve the failure on this test so
+            // neither sequential nor parallel registration aborts the rest of the request.
+            if (isForExecution)
+            {
+                try
+                {
+                    // Track only objects that already exist. Tracking is idempotent if
+                    // argument registration completed before a later callback failed.
+                    testArgumentRegistrationService.TrackSkippedTestArguments(test.Context);
+                }
+                catch (Exception trackingException)
+                {
+                    logger.LogDebug($"Could not track the objects of registration-failed test '{test.TestId}' for disposal: {trackingException.Message}");
+                }
+            }
+
+            // A callback failure takes precedence over an earlier request to skip.
+            test.Context.SkipReason = null;
+            test.SetResult(TestState.Failed, ex);
+        }
+        finally
+        {
+            // Callbacks may have changed display formatting before failing.
+            test.Context.InvalidateDisplayNameCache();
+        }
+    }
+
+    private async Task RegisterTestCore(AbstractExecutableTest test, bool isForExecution)
     {
         var registeredReceivers = test.Context.GetTestRegisteredReceivers();
         TestRegisteredContext? registeredContext = null;
@@ -178,7 +213,6 @@ async Task InvokeRegistrationDelegatesAsync()
                 }
             }
 
-            test.Context.InvalidateDisplayNameCache();
             return;
         }
 
@@ -219,11 +253,6 @@ async Task InvokeRegistrationDelegatesAsync()
                 await InvokeRegistrationDelegatesAsync().ConfigureAwait(false);
             }
         }
-
-        // Clear the cached display name after registration events
-        // This ensures that ArgumentDisplayFormatterAttribute and similar attributes
-        // have a chance to register their formatters before the display name is finalized
-        test.Context.InvalidateDisplayNameCache();
     }
 
     /// <summary>

tests/TUnit.Engine.Tests/RegistrationFailure7525Tests.cs

@@ -0,0 +1,35 @@
+using Shouldly;
+using TUnit.Engine.Tests.Enums;
+
+namespace TUnit.Engine.Tests;
+
+public class RegistrationFailure7525Tests(TestMode testMode) : InvokableTestBase(testMode)
+{
+    [Test]
+    [Arguments("RegistrationFailureTests", 3, 1)]
+    [Arguments("ParallelRegistrationFailureTests", 8, 6)]
+    public async Task RegistrationFailureDoesNotAbortRequest(string className, int total, int passed)
+    {
+        await RunTestsWithFilter($"/*/TUnit.TestProject.Bugs._7525/{className}/*",
+        [
+            result => result.ResultSummary.Counters.Total.ShouldBe(total),
+            result => result.ResultSummary.Counters.Failed.ShouldBe(2),
+            result => result.ResultSummary.Counters.Passed.ShouldBe(passed),
+            result => result.Results.Where(x => x.Outcome == "Failed")
+                .ShouldAllBe(x => x.Output!.ErrorInfo!.Message!.Contains("Registration ")
+                    && x.Output.ErrorInfo.Message.Contains("failed (#7525)"))
+        ]);
+    }
+    [Test]
+    public async Task RegistrationFailureDisposesExistingArguments()
+    {
+        await RunTestsWithFilter("/*/TUnit.TestProject.Bugs._7525/RegistrationDisposalTests/*",
+        [
+            result => result.ResultSummary.Counters.Total.ShouldBe(2),
+            result => result.ResultSummary.Counters.Failed.ShouldBe(1),
+            result => result.ResultSummary.Counters.Passed.ShouldBe(1),
+            result => result.Results.Single(x => x.Outcome == "Failed").Output!.ErrorInfo!.Message!
+                .ShouldContain("Registration receiver failed (#7525)")
+        ]);
+    }
+}

tests/TUnit.TestProject/Bugs/7525/Tests.cs

@@ -0,0 +1,79 @@
+using TUnit.Core.Interfaces;
+using TUnit.TestProject.Attributes;
+
+namespace TUnit.TestProject.Bugs._7525;
+
+public class RegistrationFailureTests
+{
+    public sealed class ThrowingReceiverAttribute : Attribute, ITestRegisteredEventReceiver
+    {
+        public int Order => 0;
+
+        public ValueTask OnTestRegistered(TestRegisteredContext context)
+            {
+            context.SetSkipped("skip before registration failure");
+            throw new InvalidOperationException("Registration receiver failed (#7525)");
+        }
+    }
+
+    public sealed class ThrowingDelegateAttribute : DataSourceGeneratorAttribute<int>
+    {
+        protected override IEnumerable<Func<int>> GenerateDataSources(DataGeneratorMetadata metadata)
+        {
+            yield return () =>
+            {
+                metadata.TestBuilderContext.Current.Events.OnTestRegistered += async (_, _) =>
+                {
+                    await Task.Yield();
+                    throw new InvalidOperationException("Registration delegate failed (#7525)");
+                };
+                return 1;
+            };
+        }
+    }
+
+    [Test, ThrowingReceiver, EngineTest(ExpectedResult.Failure)]
+    public void ReceiverFailure() => throw new Exception("Test body must not execute");
+
+    [Test, ThrowingDelegate, EngineTest(ExpectedResult.Failure)]
+    public void DelegateFailure(int value) => throw new Exception("Test body must not execute");
+
+    [Test, EngineTest(ExpectedResult.Pass)]
+    public void UnrelatedTest() { }
+}
+
+// Eight or more tests take the parallel registration path.
+[InheritsTests]
+public class ParallelRegistrationFailureTests : RegistrationFailureTests
+{
+    [Test, Arguments(1), Arguments(2), Arguments(3), Arguments(4), Arguments(5), EngineTest(ExpectedResult.Pass)]
+    public void OtherTests(int value) { }
+}
+
+public sealed class RegistrationDisposable : IDisposable
+{
+    public static List<RegistrationDisposable> Created { get; } = [];
+    public bool IsDisposed { get; private set; }
+    public RegistrationDisposable() => Created.Add(this);
+    public IAsyncInitializer Child => throw new InvalidOperationException("tracking getter failed");
+    public void Dispose() => IsDisposed = true;
+}
+
+[EngineTest(ExpectedResult.Failure)]
+public class RegistrationDisposalTests
+{
+    public static IEnumerable<RegistrationDisposable> Values()
+    {
+        yield return new RegistrationDisposable();
+    }
+
+    [Test, RegistrationFailureTests.ThrowingReceiver, MethodDataSource(nameof(Values))]
+    public void Fails(RegistrationDisposable value) => throw new Exception("Test body must not execute");
+
+    [Test, DependsOn(nameof(Fails), ProceedOnFailure = true)]
+    public async Task ArgumentWasDisposed()
+    {
+        await Assert.That(RegistrationDisposable.Created.Count).IsEqualTo(1);
+        await Assert.That(RegistrationDisposable.Created[0].IsDisposed).IsTrue();
+    }
+}