Radberi Unittesting

Testing Philosophy

What to Test

• Handler behaviour (commands, queries)
• Business logic in domain aggregates
• Validation and error handling
• Workflow state transitions
• Multitenancy isolation

What NOT to Test

• Infrastructure implementation details
• Database queries directly (test through handlers)
• Third-party library behaviour

Mocking Strategy

xUnit v3 Patterns

Basic Test Structure

public class CreateRoomHandlerTests
{
    private readonly ISpaceHubDbContext _context;
    private readonly CreateRoomHandler _handler;

    public CreateRoomHandlerTests()
    {
        // Constructor runs before each test
        _context = Substitute.For<ISpaceHubDbContext>();
        _handler = new CreateRoomHandler(_context, Substitute.For<ILogger<CreateRoomHandler>>());
    }

    [Fact]
    public async Task Handle_WithValidCommand_ReturnsSuccess()
    {
        // Arrange
        var command = new CreateRoomCommand("R001", "Meeting Room", TestData.ProjectId);

        // Act
        var result = await _handler.Handle(command, CancellationToken.None);

        // Assert
        result.IsSuccess.Should().BeTrue();
    }
}

Async Lifecycle (Setup/Teardown)

public class RoomIntegrationTests : IAsyncLifetime
{
    private readonly PostgreSqlContainer _postgres;
    private SpaceHubDbContext _context = null!;

    public RoomIntegrationTests()
    {
        _postgres = new PostgreSqlBuilder().WithImage("postgres:16-alpine").Build();
    }

    public async Task InitializeAsync()
    {
        await _postgres.StartAsync();
        _context = CreateContext();
        await _context.Database.MigrateAsync();
    }

    public async Task DisposeAsync()
    {
        await _context.DisposeAsync();
        await _postgres.DisposeAsync();
    }
}

Parameterised Tests

[Theory]
[InlineData("")]
[InlineData(null)]
[InlineData("   ")]
public async Task Handle_WithInvalidNumber_ReturnsValidationError(string? invalidNumber)
{
    var command = new CreateRoomCommand(invalidNumber!, "Name", TestData.ProjectId);
    var result = await _handler.Handle(command, CancellationToken.None);

    result.IsSuccess.Should().BeFalse();
    result.ValidationErrors.Should().NotBeEmpty();
}

[Theory]
[MemberData(nameof(GetRoomTestCases))]
public async Task Handle_WithVariousInputs_ReturnsExpectedResult(
    string number, string name, bool expectedSuccess) { /* ... */ }

public static IEnumerable<object[]> GetRoomTestCases()
{
    yield return new object[] { "R001", "Valid Room", true };
    yield return new object[] { "", "No Number", false };
}

Reference Files

For detailed patterns, see the reference files in this skill's directory:

For Syncfusion Blazor component testing (SfGrid, SfDialog, EditForm), use the Radberi-BlazorTesting skill.

Test Data Management

Deterministic Test IDs

public static class TestData
{
    // Use deterministic UUIDs for predictable test data
    public static readonly Guid OrgAId = Guid.Parse("01945a3b-0001-7000-0000-000000000001");
    public static readonly Guid ProjectId = Guid.Parse("01945a3b-0002-7000-0000-000000000001");
    public static readonly Guid RoomId = Guid.Parse("01945a3b-0003-7000-0000-000000000001");
}

Common Gotchas

"DbContext has been disposed"

Reload from repository or use AsNoTracking() for read-only operations.

Test passes alone but fails with others

Shared state between tests. Ensure fresh setup per test via constructor/IAsyncLifetime.

DateTime comparison failures

Use FakeClock for deterministic time, or compare with tolerance:

result.CreatedAt.Should().BeCloseTo(DateTime.UtcNow, TimeSpan.FromSeconds(1));

Async test hangs

Deadlock from .Result or .Wait(). Always use await and pass CancellationToken.None.

NSubstitute "Could not find a call to return from"

Ensure interface is mocked (not concrete class), use Arg.Any<T>() correctly.

Naming Convention

Follow Method_Scenario_ExpectedResult:

[Fact] public async Task Handle_WithValidCommand_ReturnsSuccess()
[Fact] public async Task Handle_WithInvalidProject_ReturnsNotFound()
[Fact] public void Create_WithNegativeArea_ThrowsArgumentOutOfRangeException()

Quick Reference

Related Skills