NextUnit 1.6.0

NextUnit - Modern Testing for .NET 10+

NextUnit is a modern, high-performance test framework for .NET 10+ that combines:

• TUnit's modern architecture - Microsoft.Testing.Platform, Native AOT, source generators
• xUnit's familiar assertions - Classic Assert.Equal(expected, actual), no fluent syntax

Quick Start

Installation

Simple - One Package (Recommended):

dotnet add package NextUnit

This meta-package includes everything you need:

• NextUnit.Core - Attributes, assertions, execution engine
• NextUnit.Generator - Source generator for zero-reflection discovery
• NextUnit.Platform - Microsoft.Testing.Platform integration
• Microsoft.Testing.Platform - Required platform dependency

Advanced - Individual Packages:

dotnet add package NextUnit.Core
dotnet add package NextUnit.Generator
dotnet add package NextUnit.Platform
dotnet add package Microsoft.Testing.Platform

Configure Your Test Project

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net10.0</TargetFramework>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="NextUnit" Version="1.6.0" />
  </ItemGroup>
</Project>

Entry Point (Optional)

The NextUnit source generator automatically creates a Program.cs entry point for your test project if one doesn't exist. You can skip this step unless you need custom configuration.

When to provide your own Program.cs:

• Custom test application configuration
• Additional testing extensions or middleware
• Custom logging or diagnostic setup

If you need customization, create a Program.cs file:

using Microsoft.Testing.Platform.Builder;
using NextUnit.Platform;

var builder = await TestApplication.CreateBuilderAsync(args);
builder.AddNextUnit();
// Add your custom configuration here
using var app = await builder.BuildAsync();
return await app.RunAsync();

Write Your First Test

using NextUnit;

public class CalculatorTests
{
    [Test]
    public void Add_TwoNumbers_ReturnsSum()
    {
        var result = 2 + 2;
        Assert.Equal(4, result);
    }

    [Test]
    [Arguments(1, 2, 3)]
    [Arguments(5, 5, 10)]
    public void Add_Parameterized(int a, int b, int expected)
    {
        Assert.Equal(expected, a + b);
    }
}

Run Tests

dotnet run

Key Features

• Zero-reflection execution - 50x faster test discovery via source generators
• Rich assertions - Collections, strings, numerics with great error messages
• Multi-scope lifecycle - Test, Class, Assembly scopes
• Parallel control - [ParallelLimit], [NotInParallel]
• Test dependencies - [DependsOn] for ordered execution
• Native AOT compatible - Full trim and AOT support

Packages

Total Size: 72.4 KB (ultra-lightweight!)

Documentation

• Getting Started Guide
• Migration from xUnit
• Best Practices
• Full Documentation

What's Different from xUnit?

Performance

• Test Discovery: ~2ms for 1,000 tests (50x faster than xUnit)
• Execution: ~540ms for 1,000 tests with parallel execution
• Per-test Overhead: ~0.54ms per simple test
• Throughput: 1,852 tests/second
• Framework Memory: ~5MB baseline
• Zero reflection in execution path

Contributing

Contributions welcome! See our Contributing Guide.

License

MIT License

Acknowledgments

Inspired by:

• TUnit - Modern architecture, source generators
• xUnit - Ergonomic assertions, proven patterns
• NUnit/MSTest - Battle-tested reliability

Built with love for .NET 10+ developers who want modern performance with familiar syntax