refactor: improve concurrent test cases for mock setup (#607)

This pull request updates unit tests and test helpers to improve test reliability and correctness, especially around method and indexer setup matching. The most significant changes include fixing the logic for determining the latest matching setup in tests and introducing a new `FakeMethodMatch` helper class.

**Test logic improvements:**

* Updated `GetLatestOrDefault_ShouldReturnLatestMatching` in `MockSetupsTests.MethodSetupsTests.cs` to check that the latest added matching setup is returned, aligning with expected behavior.
* Refactored `ThreadSafety_ConcurrentAddsAndQueries_ShouldReturnConsistentMatches` in `MockSetupsTests.IndexerSetupsTests.cs` to more accurately track and assert the latest matching setup under concurrent conditions, removing unnecessary helper methods and using `Interlocked.Exchange` for thread safety.

**Test helper enhancements:**

* Added a new `FakeMethodMatch` class to `TestHelpers/FakeMethodSetup.cs` to allow configurable matching logic for method setups in tests.
* Updated `FakeMethodSetup` to use `FakeMethodMatch` for more flexible and accurate test setup.

**Other:**

* Added missing `System.Threading` using directive to `MockSetupsTests.IndexerSetupsTests.cs` to support thread-safe operations.

Author: vbreuss

Tests/Mockolate.Internal.Tests/MockSetupsTests.IndexerSetupsTests.cs

@@ -39,8 +39,8 @@ public async Task Stress_ShouldMaintainCountAfterManyAdds()
 		public async Task ThreadSafety_ConcurrentAddsAndQueries_ShouldReturnConsistentMatches()
 		{
 			MockSetups.IndexerSetups setups = new();
-			FakeIndexerSetup matchSetup = new(true);
-			setups.Add(matchSetup);
+			FakeIndexerSetup initialMatch = new(true);
+			setups.Add(initialMatch);
 			Parallel.For(0, 200, i =>
 			{
 				bool shouldMatch = i % 2 == 0;
@@ -49,24 +49,13 @@ public async Task ThreadSafety_ConcurrentAddsAndQueries_ShouldReturnConsistentMa
 				FakeIndexerAccess access = new();
 				_ = setups.GetLatestOrDefault(access);
 			});
-			FakeIndexerSetup expected = GetExpectedMatchingSetup(setups);
+			FakeIndexerSetup finalMatch = new(true);
+			setups.Add(finalMatch);
 			FakeIndexerAccess finalAccess = new();
-			IndexerSetup? result = setups.GetLatestOrDefault(finalAccess);
-
-			await That(result).IsSameAs(expected);
 
-			static FakeIndexerSetup GetExpectedMatchingSetup(MockSetups.IndexerSetups setups)
-			{
-				IndexerSetup? latest = setups.GetLatestOrDefault(new FakeIndexerAccess());
-				if (latest is FakeIndexerSetup { ShouldMatch: true, } castLatest)
-				{
-					return castLatest;
-				}
+			IndexerSetup? result = setups.GetLatestOrDefault(finalAccess);
 
-				FakeIndexerSetup matching = new(true);
-				setups.Add(matching);
-				return matching;
-			}
+			await That(result).IsEqualTo(finalMatch);
 		}
 
 		[Fact]

Tests/Mockolate.Internal.Tests/MockSetupsTests.MethodSetupsTests.cs

@@ -29,9 +29,9 @@ public async Task GetLatestOrDefault_ShouldReturnLatestMatching()
 			setups.Add(setup1);
 			setups.Add(setup2);
 
-			MethodSetup? result = setups.GetLatestOrDefault(s => s == setup1);
+			MethodSetup? result = setups.GetLatestOrDefault(_ => true);
 
-			await That(result).IsEqualTo(setup1);
+			await That(result).IsEqualTo(setup2);
 		}
 
 		[Fact]

Tests/Mockolate.Internal.Tests/TestHelpers/FakeMethodSetup.cs

@@ -3,9 +3,16 @@
 
 namespace Mockolate.Internal.Tests.TestHelpers;
 
+internal sealed class FakeMethodMatch : IMethodMatch
+{
+	private readonly bool _matches;
+	internal FakeMethodMatch(bool matches) { _matches = matches; }
+	public bool Matches(MethodInvocation methodInvocation) => _matches;
+}
+
 internal sealed class FakeMethodSetup : MethodSetup
 {
-	internal FakeMethodSetup() : base(null!) { }
+	internal FakeMethodSetup() : base(new FakeMethodMatch(true)) { }
 	protected override bool? GetSkipBaseClass() => null;
 	protected override T SetOutParameter<T>(string parameterName, Func<T> defaultValueGenerator) => default!;
 	protected override T SetRefParameter<T>(string parameterName, T value, MockBehavior behavior) => value;