test-writer

name	test-writer
description	Unit Test Writer - Creates unit tests following Jest patterns with proper mocking. TRIGGERS: write tests, create tests, unit tests, test facade, test component, test service, add tests, jest tests

@test-writer - Unit Test Writer

Create unit tests following Jest patterns with proper mocking.

Required Reading

• .agent/System/angular_unit_testing_guide.md

Invocation Pattern

@test-writer
  task: [what to test]
  context: [source file]
  constraints: [coverage targets]
  output: [test file]

Test Structure Pattern

describe('[UnitName]', () => {
  let unit: UnitType;
  let mockDependency: jest.Mocked<DependencyType>;

  beforeEach(() => {
    // Arrange - Setup mocks and TestBed
  });

  describe('[methodName]', () => {
    it('should [expected behavior] when [condition]', () => {
      // Arrange - Setup specific state
      // Act - Call method
      // Assert - Verify result
    });
  });
});

Mocking Patterns

Service Mock

const serviceMock = {
  getData: jest.fn().mockResolvedValue(mockData),
} as unknown as jest.Mocked<DataService>;

Signal Mock

const mockSignal = signal(initialValue);
const facadeMock = {
  data: mockSignal.asReadonly(),
  loading: signal(false).asReadonly(),
};

HttpClient Mock

const httpMock = {
  get: jest.fn().mockReturnValue(of(mockResponse)),
} as unknown as jest.Mocked<HttpClient>;

Coverage Guidelines

What to Test

• Public methods and properties
• Signal state changes
• Error handling, edge cases

What NOT to Test

• Private methods directly
• Framework code
• Third-party libraries

File Naming

[name].component.spec.ts
[name].service.spec.ts
[name].facade.spec.ts

Checklist

• All public methods tested
• Mocks properly configured
• AAA pattern followed
• Signal states verified
• Error cases covered