# Angular Testing

> Angular testing patterns with Jest and TestBed. Covers unit tests for use cases, queries, services, and components using AAA pattern, mock repositories via InjectionToken, and signal-based component testing. Use when creating .spec.ts files, writing tests, or when the user mentions testing. ALWAYS use when generating test files. Use when this capability is needed.

- Skill: `tomevault-io/angular-testing-2` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add tomevault-io/angular-testing-2`
- Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/angular-testing-2/raw
- Safety review: pending (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Web & Frontend
- Author: tomevault-io (https://skillmd.com/u/tomevault-io)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/tomevault-io/angular-testing-2

---


# Angular Testing Patterns

Jest + TestBed with AAA (Arrange/Act/Assert) pattern.

## Test File Location

Test files live next to the source file: `entity.service.ts` → `entity.service.spec.ts`

## Core Pattern: TestBed + InjectionToken Mocks

```typescript
import { TestBed } from '@angular/core/testing';

describe('CreateEntityUseCase', () => {
  let useCase: CreateEntityUseCase;
  let mockRepository: jest.Mocked<EntityRepository>;

  beforeEach(() => {
    mockRepository = {
      find: jest.fn(),
      findById: jest.fn(),
      create: jest.fn(),
      update: jest.fn(),
      delete: jest.fn(),
    };

    TestBed.configureTestingModule({
      providers: [
        CreateEntityUseCase,
        { provide: ENTITY_REPOSITORY, useValue: mockRepository },
        { provide: AuthService, useValue: { getCurrentUser: () => ({ id: 1 }) } },
      ],
    });

    useCase = TestBed.inject(CreateEntityUseCase);
  });

  it('should create entity successfully', async () => {
    // Arrange
    const request = { name: 'Test Entity' };
    const expected = { id: 1, name: 'Test Entity' };
    mockRepository.create.mockResolvedValue(Result.success(expected));

    // Act
    const result = await useCase.execute(request);

    // Assert
    expect(result.isSuccess).toBe(true);
    expect(result.value).toEqual(expected);
    expect(mockRepository.create).toHaveBeenCalled();
  });

  it('should return failure when name is empty', async () => {
    const result = await useCase.execute({ name: '' });
    expect(result.isFailure).toBe(true);
  });
});
```

## Signal Testing

```typescript
it('should update signal state', () => {
  const service = TestBed.inject(EntityListStateService);

  service.setKeyword('test');

  expect(service.keyword()).toBe('test');
  expect(service.page()).toBe(1); // reset on filter change
});
```

## Detailed Patterns

- UseCase/Query tests: [references/usecase-testing.md](references/usecase-testing.md)
- Component tests: [references/component-testing.md](references/component-testing.md)
- State service tests: [references/state-service-testing.md](references/state-service-testing.md)

---
> Source: [cuongtl1992/vibe-skills](https://github.com/cuongtl1992/vibe-skills) — distributed by [TomeVault](https://tomevault.io).
<!-- tomevault:4.0:skill_md:2026-06-16 -->