A .NET Testing Framework
$ dotnet add package TUnit.Engine
A modern .NET testing framework. Tests are source-generated at compile time, run in parallel by default, and support Native AOT — all built on Microsoft.Testing.Platform.
[DependsOn] to express ordering and [ParallelLimiter] to cap concurrency[Arguments], [Matrix], [ClassData], and custom DataSourceGenerator<T> sourcesasync, incorrect method signatures, and invalid attribute combinations[Before] / [After] at method, class, assembly, or test session scopedotnet new install TUnit.Templates
dotnet new TUnit -n "MyTestProject"
cd MyTestProject
dotnet rundotnet add package TUnit[Test]
public async Task Parsing_A_Valid_Date_Succeeds()
{
var date = DateTime.Parse("2025-01-01");
await Assert.That(date.Year).IsEqualTo(2025);
await Assert.That(date.Month).IsEqualTo(1);
}[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 — generates a test for every combination (9 total here)
[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();
}[Before(Class)]
public static async Task SetupDatabase(ClassHookContext context)
{
await DatabaseHelper.InitializeAsync();
}
[Test]
[MethodDataSource(nameof(GetTestUsers))]
public async Task Register_User(string username, string password) { ... }
[Test, DependsOn(nameof(Register_User))]
[Retry(3)]
public async Task Login_With_Registered_User(string username, string password)
{
// Guaranteed to run after Register_User passes
}Extend built-in base classes to create your own skip conditions, retry logic, and more:
public class WindowsOnlyAttribute : SkipAttribute
{
public WindowsOnlyAttribute() : base("Windows only") { }
public override Task<bool> ShouldSkip(TestContext testContext)
=> Task.FromResult(!OperatingSystem.IsWindows());
}
[Test, WindowsOnly]
public async Task Windows_Specific_Feature() { ... }See the documentation for more examples, including custom retry logic and data sources.
| IDE | Notes |
|---|---|
| Visual Studio 2022 (17.13+) | Works out of the box |
| Visual Studio 2022 (earlier) | Enable "Use testing platform server mode" in Tools > Manage Preview Features |
| JetBrains Rider | Enable "Testing Platform support" in Settings > Build, Execution, Deployment > Unit Testing > Testing Platform |
| VS Code | Install C# Dev Kit and enable "Use Testing Platform Protocol" |
| CLI | Works with dotnet test, dotnet run, and direct execution |
| Package | Purpose |
|---|---|
TUnit | Start here — the full framework (Core + Engine + Assertions) |
TUnit.Core | Shared test library components without an execution engine |
TUnit.Engine | Execution engine for test projects |
TUnit.Assertions | Standalone assertions — works with other test frameworks too |
TUnit.Playwright | Playwright integration with automatic browser lifecycle management |
The syntax will feel familiar. For example, xUnit's [Fact] becomes [Test], and [Theory] + [InlineData] becomes [Test] + [Arguments]. See the migration guides for full details: xUnit · NUnit · MSTest.