Generate Tests

Generate Tests

Generate unit and integration tests following project conventions. Analyzes the target code, identifies test scenarios, and scaffolds test classes with proper mocking and assertions.

Arguments

• {target} -- Handler, entity, or class name to test (e.g., CreateOrderHandler, Order, OrderEndpoints)
• {service} -- Target microservice (optional, auto-detected from file location)
• --integration -- Also generate integration tests with Testcontainers
• --coverage -- Generate tests for all untested handlers in a service

Configuration

Read cloudstack.json from the project root at the start of execution. Extract:

• NAMESPACE = project.namespace (default: detect from *.sln)
• SERVICES = backend.services[] (default: discover from project structure)
• SOLUTION = backend.solutionPath (default: find *.sln)
• MESSAGING = backend.messaging (default: wolverinefx)
• RESULT_PATTERN = backend.resultPattern (default: true)

If cloudstack.json does not exist, auto-detect by scanning the project structure.

Process

Step 1: Locate the target

# Find the file containing the target class
grep -rl "class {target}" src/ --include="*.cs" | head -5

Read the target file completely. Identify:

• Is it a command handler? (method returns Result<T>, takes a command record)
• Is it a query handler? (method returns Result<T>, takes a query record)
• Is it an entity? (inherits from Entity<TId> or AggregateRoot<TId>)
• Is it an event handler? (handles domain/integration events)
• Is it an endpoint? (static class with MapEndpoints)

Step 2: Analyze dependencies

Read the constructor to find injected dependencies:

grep -A 20 "class {target}" <file> | grep -E "private readonly|ILogger|I[A-Z]"

For each dependency, determine:

• Repository interfaces → mock with NSubstitute
• External services → mock with NSubstitute
• ILogger → mock or use NullLogger
• DbContext → use in-memory for unit, Testcontainers for integration

Step 3: Identify test scenarios

For command handlers:

• Happy path (valid input → success result)
• Validation failure (invalid input → validation error)
• Not found (referenced entity doesn't exist → failure result)
• Duplicate (entity already exists → conflict error)
• Domain rule violation (business rule broken → failure result)

For query handlers:

• Happy path (entity exists → returns DTO)
• Not found (entity doesn't exist → failure result)
• Pagination (list query → correct page/size)
• Filtering (filtered query → correct subset)

For entities:

• Factory method creates valid entity
• Required fields enforced
• Domain events raised on state changes
• Value object equality

For event handlers:

• Handler processes event successfully
• Handler is idempotent (processing same event twice)

Step 4: Determine test project location

# Find existing test projects for this service
find tests/ -name "*.csproj" | grep -i "{service}"

If no test project exists, note it and suggest creating one.

Step 5: Generate unit tests

Create test file at tests/{Service}.UnitTests/ or alongside existing tests:

namespace {Namespace}.{Service}.UnitTests;

public class {Target}Tests
{
    private readonly I{Repository} _repository;
    private readonly {Target} _sut;

    public {Target}Tests()
    {
        _repository = Substitute.For<I{Repository}>();
        _sut = new {Target}(_repository);
    }

    [Fact]
    public async Task Handle_ValidCommand_ReturnsSuccess()
    {
        // Arrange
        var command = new {Command} { /* valid data */ };
        _repository.GetById(Arg.Any<{Id}>())
            .Returns(/* expected entity */);

        // Act
        var result = await _sut.Handle(command);

        // Assert
        result.IsSuccess.Should().BeTrue();
        await _repository.Received(1).Add(Arg.Any<{Entity}>());
    }

    [Fact]
    public async Task Handle_NotFound_ReturnsFailure()
    {
        // Arrange
        var command = new {Command} { /* data referencing nonexistent entity */ };
        _repository.GetById(Arg.Any<{Id}>())
            .Returns(({Entity}?)null);

        // Act
        var result = await _sut.Handle(command);

        // Assert
        result.IsSuccess.Should().BeFalse();
        result.Error.Code.Should().Be("{ENTITY}_NOT_FOUND");
    }
}

Adapt the template based on what the handler actually does — read the real code, don't guess.

Step 6: Generate integration tests (if --integration)

If using unfamiliar Testcontainers or WireMock patterns, use context7 to look up the current API.

namespace {Namespace}.{Service}.IntegrationTests;

public class {Target}IntegrationTests : IClassFixture<IntegrationTestFactory>
{
    private readonly IntegrationTestFactory _factory;

    public {Target}IntegrationTests(IntegrationTestFactory factory)
    {
        _factory = factory;
    }

    [Fact]
    [Trait("Category", "Integration")]
    public async Task {Endpoint}_ReturnsExpectedResult()
    {
        // Arrange
        var client = _factory.CreateClient();

        // Act
        var response = await client.PostAsJsonAsync("/api/{resource}", new { /* data */ });

        // Assert
        response.StatusCode.Should().Be(HttpStatusCode.Created);
    }
}

Step 7: Coverage mode (if --coverage)

If --coverage was passed:

# Find all handlers in the service
grep -rl "class.*Handler" src/{Service}/ --include="*.cs" | sort

# Find existing tests
grep -rl "class.*Tests" tests/ --include="*.cs" | sort

# Diff to find untested handlers

Generate tests for each untested handler, one file per handler.

Output

## Generated Tests: {target}

Files created:
- `tests/{Service}.UnitTests/{Target}Tests.cs` ({N} test methods)
- `tests/{Service}.IntegrationTests/{Target}IntegrationTests.cs` ({M} test methods) [if --integration]

Test scenarios covered:
- {list of scenarios}

Run: `dotnet test tests/{Service}.UnitTests --filter {Target}Tests`

Error Handling

• Target not found: Search for partial matches and suggest alternatives
• No test project: Suggest creating one with dotnet new xunit
• Complex dependencies: If handler has 5+ dependencies, note which are mocked and suggest reviewing whether the handler has too many responsibilities

Checklist

• Uses xUnit [Fact] and [Theory] attributes
• Uses NSubstitute for mocking (Substitute.For<T>())
• Uses FluentAssertions (.Should().)
• Follows Arrange-Act-Assert pattern
• Test class name matches {Target}Tests
• Integration tests have [Trait("Category", "Integration")]
• No hardcoded GUIDs — use Guid.NewGuid() or typed ID .New()

Related Skills

• /dotnet-architect:add-command -- Scaffold the handler first, then generate tests
• /dotnet-architect:add-query -- Same pattern for query handlers
• /dev-workflow:run-tests -- Run the generated tests