xUnit Skill

xUnit is the testing framework to use. Tests use Shouldly for readable assertions and Nsubstitute for mocking. All tests follow strict MethodName_Scenario_ExpectedBehavior naming.

Quick Start

Unit Test Structure

csharp
1public class WalletManagerTests
2{
3    private readonly Mock<IRepository<Wallet>> _mockRepository;
4    private readonly WalletManager _sut;
5
6    public WalletManagerTests()
7    {
8        _mockRepository = new Mock<IRepository<Wallet>>();
9        _sut = new WalletManager(_mockRepository.Object);
10    }
11
12    [Fact]
13    public async Task CreateAsync_ValidWallet_ReturnsSuccess()
14    {
15        // Arrange
16        var wallet = new Wallet { Name = "Test" };
17        _mockRepository.Setup(r => r.AddAsync(wallet)).ReturnsAsync(wallet);
18
19        // Act
20        var result = await _sut.CreateAsync(wallet);
21
22        // Assert
23        result.IsSuccess.Should().BeTrue();
24        result.Value.Should().Be(wallet);
25    }
26}

Theory with InlineData

csharp
1[Theory]
2[InlineData(12)]
3[InlineData(15)]
4[InlineData(18)]
5[InlineData(21)]
6[InlineData(24)]
7public void GenerateMnemonic_ValidWordCount_ReturnsCorrectLength(int wordCount)
8{
9    var result = _keyManager.GenerateMnemonic(wordCount);
10
11    result.IsSuccess.Should().BeTrue();
12    result.Value!.Split(' ').Should().HaveCount(wordCount);
13}

Key Concepts

Common Patterns

Exception Testing

csharp
1[Fact]
2public void Constructor_NullRepository_ThrowsArgumentNullException()
3{
4    var act = () => new WalletManager(null!);
5
6    act.Should().Throw<ArgumentNullException>()
7        .WithParameterName("repository");
8}
9
10[Fact]
11public async Task ProcessAsync_InvalidData_ThrowsWithMessage()
12{
13    var exception = await Assert.ThrowsAsync<InvalidOperationException>(
14        () => _processor.ProcessAsync(invalidContext));
15
16    exception.Message.Should().Contain("validation failed");
17}

Async Test Pattern

csharp
1[Fact]
2public async Task ExecuteAsync_ValidBlueprint_CompletesSuccessfully()
3{
4    // Arrange
5    var blueprint = CreateTestBlueprint();
6
7    // Act
8    var result = await _engine.ExecuteAsync(blueprint);
9
10    // Assert
11    result.Success.Should().BeTrue();
12    result.ProcessedData.Should().ContainKey("output");
13}

See Also

• patterns - Test patterns and anti-patterns
• workflows - Test workflows and fixtures

Related Skills

• See the dotnet-testing-nsubstitute-mocking skill for mocking dependencies
• See the entity-framework skill for database testing with InMemory provider

Documentation Resources

Fetch latest xUnit documentation with Context7.

How to use Context7:

1. Use mcp__context7__resolve-library-id to search for "xunit"
2. Query with mcp__context7__query-docs using the resolved library ID

Library ID: /xunit/xunit.net (875 code snippets, High reputation)

Recommended Queries:

• "xUnit Theory InlineData patterns"
• "IClassFixture ICollectionFixture shared context"
• "IAsyncLifetime async setup teardown"
• "xUnit parallel test execution configuration"