TUnit.Assertions 0.25.21

🚀 The Modern Testing Framework for .NET

TUnit is a next-generation testing framework for C# that outpaces traditional frameworks with source-generated tests, parallel execution by default, and Native AOT support. Built on the modern Microsoft.Testing.Platform, TUnit delivers faster test runs, better developer experience, and unmatched flexibility.

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⚡ Why Choose TUnit?

⚡ Parallel by Default - Tests run concurrently with intelligent dependency management

🎯 Compile-Time Discovery - Know your test structure before runtime

🔧 Modern .NET Ready - Native AOT, trimming, and latest .NET features

🎭 Extensible - Customize data sources, attributes, and test behavior

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📚 Complete Documentation & Learning Center

🚀 New to TUnit? Start with our Getting Started Guide

🔄 Migrating? See our Migration Guides

🎯 Advanced Features? Explore Data-Driven Testing, Test Dependencies, and Parallelism Control

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🏁 Quick Start

Using the Project Template (Recommended)

dotnet new install TUnit.Templates
dotnet new TUnit -n "MyTestProject"

Manual Installation

dotnet add package TUnit --prerelease

📖 📚 Complete Documentation & Guides - Everything you need to master TUnit

✨ Key Features

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🚀 Performance & Modern Platform

• 🔥 Source-generated tests (no reflection)
• ⚡ Parallel execution by default
• 🚀 Native AOT & trimming support
• 📈 Optimized for performance

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🎯 Advanced Test Control

• 🔗 Test dependencies with [DependsOn]
• 🎛️ Parallel limits & custom scheduling
• 🛡️ Built-in analyzers & compile-time checks
• 🎭 Custom attributes & extensible conditions

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📊 Rich Data & Assertions

• 📋 Multiple data sources ([Arguments], [Matrix], [ClassData])
• ✅ Fluent async assertions
• 🔄 Smart retry logic & conditional execution
• 📝 Rich test metadata & context

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🔧 Developer Experience

• 💉 Full dependency injection support
• 🪝 Comprehensive lifecycle hooks
• 🎯 IDE integration (VS, Rider, VS Code)
• 📚 Extensive documentation & examples

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📝 Simple Test Example

[Test]
public async Task User_Creation_Should_Set_Timestamp()
{
    // Arrange
    var userService = new UserService();

    // Act
    var user = await userService.CreateUserAsync("john.doe@example.com");

    // Assert - TUnit's fluent assertions
    await Assert.That(user.CreatedAt)
        .IsEqualTo(DateTime.Now)
        .Within(TimeSpan.FromMinutes(1));

    await Assert.That(user.Email)
        .IsEqualTo("john.doe@example.com");
}

🎯 Data-Driven Testing

[Test]
[Arguments("user1@test.com", "ValidPassword123")]
[Arguments("user2@test.com", "AnotherPassword456")]
[Arguments("admin@test.com", "AdminPass789")]
public async Task User_Login_Should_Succeed(string email, string password)
{
    var result = await authService.LoginAsync(email, password);
    await Assert.That(result.IsSuccess).IsTrue();
}

// Matrix testing - tests all combinations
[Test]
[MatrixDataSource]
public async Task Database_Operations_Work(
    [Matrix("Create", "Update", "Delete")] string operation,
    [Matrix("User", "Product", "Order")] string entity)
{
    await Assert.That(await ExecuteOperation(operation, entity))
        .IsTrue();
}

🔗 Advanced Test Orchestration

[Before(Class)]
public static async Task SetupDatabase(ClassHookContext context)
{
    await DatabaseHelper.InitializeAsync();
}

[Test, DisplayName("Register a new account")]
[MethodDataSource(nameof(GetTestUsers))]
public async Task Register_User(string username, string password)
{
    // Test implementation
}

[Test, DependsOn(nameof(Register_User))]
[Retry(3)] // Retry on failure
public async Task Login_With_Registered_User(string username, string password)
{
    // This test runs after Register_User completes
}

[Test]
[ParallelLimit<LoadTestParallelLimit>] // Custom parallel control
[Repeat(100)] // Run 100 times
public async Task Load_Test_Homepage()
{
    // Performance testing
}

// Custom attributes
[Test, WindowsOnly, RetryOnHttpError(5)]
public async Task Windows_Specific_Feature()
{
    // Platform-specific test with custom retry logic
}

public class LoadTestParallelLimit : IParallelLimit
{
    public int Limit => 10; // Limit to 10 concurrent executions
}

🔧 Smart Test Control

// Custom conditional execution
public class WindowsOnlyAttribute : SkipAttribute
{
    public WindowsOnlyAttribute() : base("Windows only test") { }

    public override Task<bool> ShouldSkip(TestContext testContext)
        => Task.FromResult(!OperatingSystem.IsWindows());
}

// Custom retry logic
public class RetryOnHttpErrorAttribute : RetryAttribute
{
    public RetryOnHttpErrorAttribute(int times) : base(times) { }

    public override Task<bool> ShouldRetry(TestInformation testInformation,
        Exception exception, int currentRetryCount)
        => Task.FromResult(exception is HttpRequestException { StatusCode: HttpStatusCode.ServiceUnavailable });
}

🎯 Perfect For Every Testing Scenario

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🧪 Unit Testing

[Test]
[Arguments(1, 2, 3)]
[Arguments(5, 10, 15)]
public async Task Calculate_Sum(int a, int b, int expected)
{
    await Assert.That(Calculator.Add(a, b))
        .IsEqualTo(expected);
}

Fast, isolated, and reliable

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🔗 Integration Testing

[Test, DependsOn(nameof(CreateUser))]
public async Task Login_After_Registration()
{
    // Runs after CreateUser completes
    var result = await authService.Login(user);
    await Assert.That(result.IsSuccess).IsTrue();
}

Stateful workflows made simple

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⚡ Load Testing

[Test]
[ParallelLimit<LoadTestLimit>]
[Repeat(1000)]
public async Task API_Handles_Concurrent_Requests()
{
    await Assert.That(await httpClient.GetAsync("/api/health"))
        .HasStatusCode(HttpStatusCode.OK);
}

Built-in performance testing

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🚀 What Makes TUnit Different?

Compile-Time Intelligence

Tests are discovered at build time, not runtime - enabling faster discovery, better IDE integration, and precise resource lifecycle management.

Parallel-First Architecture

Built for concurrency from day one with [DependsOn] for test chains, [ParallelLimit] for resource control, and intelligent scheduling.

Extensible by Design

The DataSourceGenerator<T> pattern and custom attribute system let you extend TUnit's capabilities without modifying core framework code.

🏆 Community & Ecosystem

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🌟 Join thousands of developers modernizing their testing

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🤝 Active Community

• 📚 Official Documentation - Comprehensive guides, tutorials, and API reference
• 💬 GitHub Discussions - Get help and share ideas
• 🐛 Issue Tracking - Report bugs and request features
• 📢 Release Notes - Stay updated with latest improvements

🛠️ IDE Support

TUnit works seamlessly across all major .NET development environments:

Visual Studio (2022 17.13+)

✅ Fully supported - No additional configuration needed for latest versions

⚙️ Earlier versions: Enable "Use testing platform server mode" in Tools > Manage Preview Features

JetBrains Rider

✅ Fully supported

⚙️ Setup: Enable "Testing Platform support" in Settings > Build, Execution, Deployment > Unit Testing > VSTest

Visual Studio Code

✅ Fully supported

⚙️ Setup: Install C# Dev Kit and enable "Use Testing Platform Protocol"

Command Line

✅ Full CLI support - Works with dotnet test, dotnet run, and direct executable execution

📦 Package Options

🎯 Migration from Other Frameworks

Coming from NUnit or xUnit? TUnit maintains familiar syntax while adding modern capabilities:

// Enhanced with TUnit's advanced features
[Test]
[Arguments("value1")]
[Arguments("value2")]
[Retry(3)]
[ParallelLimit<CustomLimit>]
public async Task Modern_TUnit_Test(string value) { }

📖 Need help migrating? Check our detailed Migration Guides with step-by-step instructions for xUnit, NUnit, and MSTest.

💡 Current Status

The API is mostly stable, but may have some changes based on feedback or issues before v1.0 release.

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🚀 Ready to Experience the Future of .NET Testing?

⚡ Start in 30 Seconds

# Create a new test project with examples
dotnet new install TUnit.Templates && dotnet new TUnit -n "MyAwesomeTests"

# Or add to existing project
dotnet add package TUnit --prerelease

🎯 Why Wait? Join the Movement

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📈 Performance

Optimized execution Parallel by default Zero reflection overhead

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🔮 Future-Ready

Native AOT support Latest .NET features Source generation

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🛠️ Developer Experience

Compile-time checks Rich IDE integration Intelligent debugging

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🎭 Flexibility

Test dependencies Custom attributes Extensible architecture

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📖 Learn More: tunit.dev | 💬 Get Help: GitHub Discussions | ⭐ Show Support: Star on GitHub

TUnit is actively developed and production-ready. Join our growing community of developers who've made the switch!

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Performance Benchmark

Scenario: Building the test project

macos-latest

BenchmarkDotNet v0.15.1, macOS Sonoma 14.7.6 (23H626) [Darwin 23.6.0]
Apple M1 (Virtual), 1 CPU, 3 logical and 3 physical cores
.NET SDK 9.0.300
  [Host]   : .NET 9.0.5 (9.0.525.21509), Arm64 RyuJIT AdvSIMD
  .NET 9.0 : .NET 9.0.5 (9.0.525.21509), Arm64 RyuJIT AdvSIMD

Job=.NET 9.0  Runtime=.NET 9.0  

ubuntu-latest

BenchmarkDotNet v0.15.1, Linux Ubuntu 24.04.2 LTS (Noble Numbat)
AMD EPYC 7763, 1 CPU, 4 logical and 2 physical cores
.NET SDK 9.0.300
  [Host]   : .NET 9.0.5 (9.0.525.21509), X64 RyuJIT AVX2
  .NET 9.0 : .NET 9.0.5 (9.0.525.21509), X64 RyuJIT AVX2

Job=.NET 9.0  Runtime=.NET 9.0  

windows-latest

BenchmarkDotNet v0.15.1, Windows 10 (10.0.20348.3561) (Hyper-V)
AMD EPYC 7763 2.44GHz, 1 CPU, 4 logical and 2 physical cores
.NET SDK 9.0.300
  [Host]   : .NET 9.0.5 (9.0.525.21509), X64 RyuJIT AVX2
  .NET 9.0 : .NET 9.0.5 (9.0.525.21509), X64 RyuJIT AVX2

Job=.NET 9.0  Runtime=.NET 9.0  

Scenario: A single test that completes instantly (including spawning a new process and initialising the test framework)

macos-latest

BenchmarkDotNet v0.15.1, macOS Sonoma 14.7.6 (23H626) [Darwin 23.6.0]
Apple M1 (Virtual), 1 CPU, 3 logical and 3 physical cores
.NET SDK 9.0.300
  [Host]   : .NET 9.0.5 (9.0.525.21509), Arm64 RyuJIT AdvSIMD
  .NET 9.0 : .NET 9.0.5 (9.0.525.21509), Arm64 RyuJIT AdvSIMD

Job=.NET 9.0  Runtime=.NET 9.0  

ubuntu-latest

BenchmarkDotNet v0.15.1, Linux Ubuntu 24.04.2 LTS (Noble Numbat)
AMD EPYC 7763, 1 CPU, 4 logical and 2 physical cores
.NET SDK 9.0.300
  [Host]   : .NET 9.0.5 (9.0.525.21509), X64 RyuJIT AVX2
  .NET 9.0 : .NET 9.0.5 (9.0.525.21509), X64 RyuJIT AVX2

Job=.NET 9.0  Runtime=.NET 9.0  

windows-latest

BenchmarkDotNet v0.15.1, Windows 10 (10.0.20348.3561) (Hyper-V)
AMD EPYC 7763 2.44GHz, 1 CPU, 4 logical and 2 physical cores
.NET SDK 9.0.300
  [Host]   : .NET 9.0.5 (9.0.525.21509), X64 RyuJIT AVX2
  .NET 9.0 : .NET 9.0.5 (9.0.525.21509), X64 RyuJIT AVX2

Job=.NET 9.0  Runtime=.NET 9.0  

Scenario: A test that takes 50ms to execute, repeated 100 times (including spawning a new process and initialising the test framework)

macos-latest

BenchmarkDotNet v0.15.1, macOS Sonoma 14.7.6 (23H626) [Darwin 23.6.0]
Apple M1 (Virtual), 1 CPU, 3 logical and 3 physical cores
.NET SDK 9.0.300
  [Host]   : .NET 9.0.5 (9.0.525.21509), Arm64 RyuJIT AdvSIMD
  .NET 9.0 : .NET 9.0.5 (9.0.525.21509), Arm64 RyuJIT AdvSIMD

Job=.NET 9.0  Runtime=.NET 9.0  

ubuntu-latest

BenchmarkDotNet v0.15.1, Linux Ubuntu 24.04.2 LTS (Noble Numbat)
AMD EPYC 7763, 1 CPU, 4 logical and 2 physical cores
.NET SDK 9.0.300
  [Host]   : .NET 9.0.5 (9.0.525.21509), X64 RyuJIT AVX2
  .NET 9.0 : .NET 9.0.5 (9.0.525.21509), X64 RyuJIT AVX2

Job=.NET 9.0  Runtime=.NET 9.0  

windows-latest

BenchmarkDotNet v0.15.1, Windows 10 (10.0.20348.3695) (Hyper-V)
AMD EPYC 7763 2.44GHz, 1 CPU, 4 logical and 2 physical cores
.NET SDK 9.0.300
  [Host]   : .NET 9.0.5 (9.0.525.21509), X64 RyuJIT AVX2
  .NET 9.0 : .NET 9.0.5 (9.0.525.21509), X64 RyuJIT AVX2

Job=.NET 9.0  Runtime=.NET 9.0