revert: migrate to TUnit

[vbreuss]

This reverts commit 3e0dab6 from #223, because Mutation testing not yet works with MTP mode

[Copilot]

Pull request overview

This PR reverts the migration from xUnit to TUnit (done in PR #223), because mutation testing does not yet work with Microsoft Testing Platform (MTP) mode that TUnit uses.

Changes:

• Replaces all TUnit test attributes ([Test], [Arguments], [MethodDataSource]) with xUnit equivalents ([Fact], [Theory], [InlineData], [MemberData])
• Updates project files to swap TUnit dependencies for xUnit packages and adjusts build pipeline scripts accordingly
• Removes the custom Record helper class and reverts Usings.cs files across all test projects

Reviewed changes

Copilot reviewed 153 out of 165 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
Tests/Directory.Build.props	Swaps TUnit engine/dependencies for xUnit, coverlet, and test SDK packages
Directory.Packages.props	Replaces TUnit and Polyfill package versions with xUnit and coverlet equivalents
Pipeline/Build.UnitTest.cs	Updates test run arguments from MTP/TUnit style to xUnit/standard dotnet test style
Pipeline/Build.MutationTests.cs	Removes --testrunner mtp flag, downgrades stryker, targets net8.0 instead of net10.0
Pipeline/Build.CodeCoverage.cs	Updates coverage report glob to match coverlet output path
Pipeline/Build.ApiChecks.cs	Updates test run arguments to xUnit/standard style
Tests/Mockolate.Tests/TestHelpers/Usings.cs	Swaps using TUnit for using Xunit
Tests/Mockolate.Tests/TestHelpers/Record.cs	Removes TUnit-specific Record helper class
All Tests/**/Usings.cs	Replaces TUnit global using with Xunit
All test .cs files	Replaces [Test]/[Arguments]/[MethodDataSource] with [Fact]/[Theory]/[InlineData]/[MemberData]
Tests/Mockolate.Tests/Internals/TypeFormatterTests.cs	Converts MethodDataSource + tuple IEnumerable to MemberData + TheoryData<T,T>
Tests/Mockolate.Api.Tests/ApiApprovalTests.cs	Converts MethodDataSource + yield to MemberData + TheoryData<T>
Tests/Mockolate.Api.Tests/ApiAcceptance.cs	Converts [Explicit] to [Fact(Explicit = true)]
Tests/Mockolate.Api.Tests/Mockolate.Api.Tests.csproj	Targets net8.0, switches to xunit.v3
Tests/Mockolate.Tests/MockDelegates/DelegateTests.cs	Mixes aweXpect assertions with Assert.True/Assert.Equal
Tests/Mockolate.Tests/Verify/VerificationResultTests.AsyncTests.cs	Adjusts timing thresholds for Within_ShouldAbortAsSoonAsConditionIsSatisfied
Tests/Mockolate.Api.Tests/Helper.cs	Removes unused using Assembly alias
Source/Mockolate/Mockolate.csproj	Unconditionally includes IsExternalInit package reference
Tests/Mockolate.ExampleTests/Mockolate.ExampleTests.csproj	Adds IsExternalInit package reference
Tests/Mockolate.Api.Tests/Expected/Mockolate_net10.0.txt	Removes [ParamCollection] attribute from API snapshot
.github/workflows/ci.yml	Removes fail-fast: false from matrix strategy
Mockolate.sln.DotSettings	Removes TUnit-specific ReSharper unit testing settings

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[github-actions]

🚀 Benchmark Results

Details

BenchmarkDotNet v0.15.8, Linux Ubuntu 24.04.3 LTS (Noble Numbat)

Intel Xeon Platinum 8370C CPU 2.80GHz (Max: 2.79GHz), 1 CPU, 4 logical and 2 physical cores

.NET SDK 10.0.103

[Host] : .NET 10.0.3 (10.0.3, 10.0.326.7603), X64 RyuJIT x86-64-v4
Job=InProcess Toolchain=InProcessEmitToolchain IterationCount=15

LaunchCount=1 WarmupCount=10

Method	Mean	Error	StdDev	Gen0	Gen1	Allocated
Simple_Mockolate	1.546 μs	0.0327 μs	0.0306 μs	0.1640	-	4.02 KB
Simple_Moq	132.298 μs	0.8410 μs	0.7455 μs	0.4883	0.2441	14.56 KB
Simple_NSubstitute	5.916 μs	0.0746 μs	0.0698 μs	0.3662	-	9.14 KB
Simple_FakeItEasy	6.095 μs	0.0426 μs	0.0378 μs	0.3281	0.0153	8.12 KB
Simple_TUnitMocks	1.980 μs	0.0736 μs	0.0575 μs	0.2632	0.0076	6.54 KB

[github-actions]

This is addressed in release v1.5.1.