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Skill · 已公开版本

tdd-workflows-tdd-red · TDD红阶段失败测试生成

按TDD红阶段原则为指定行为生成应失败的测试,覆盖正常路径、边界与异常,并给出运行验证方式。

先看看示例

作者提供的示例,实际效果取决于你的输入和使用工具。

输入

为登录服务生成红阶段测试:覆盖正确凭证返回令牌、用户不存在返回错误、空密码边界。

输出

预期交付:完整失败测试文件、测试目的说明、运行与验证失败的命令、覆盖范围清单。(编辑说明,非实际运行结果)

方法说明

---
name: tdd-workflows-tdd-red
description: "Generate failing tests for the TDD red phase to define expected behavior and edge cases."
risk: critical
source: community
date_added: "2026-02-27"
---

Write comprehensive failing tests following TDD red phase principles.

[Extended thinking: Generates failing tests that properly define expected behavior using test-automator agent.]

## Use this skill when

- Starting the TDD red phase for new behavior
- You need failing tests that capture expected behavior
- You want edge case coverage before implementation

## Do not use this skill when

- You are in the green or refactor phase
- You only need performance benchmarks
- Tests must run against production systems

## Instructions

1. Identify behaviors, constraints, and edge cases.
2. Generate failing tests that define expected outcomes.
3. Ensure failures are due to missing behavior, not setup errors.
4. Document how to run tests and verify failures.

## Safety

- Keep test data isolated and avoid production environments.
- Avoid flaky external dependencies in the red phase.

## Role

Use the current project’s test framework and available tools. The upstream Task/subagent type is host-specific and not bundled; it does not authorize delegation. Produce the tests directly when no authorized matching agent exists.

## Prompt Template

"Generate comprehensive FAILING tests for: $ARGUMENTS

## Core Requirements

1. **Test Structure**
   - Framework-appropriate setup (Jest/pytest/JUnit/Go/RSpec)
   - Arrange-Act-Assert pattern
   - should_X_when_Y naming convention
   - Isolated fixtures with no interdependencies

2. **Behavior Coverage**
   - Happy path scenarios
   - Edge cases (empty, null, boundary values)
   - Error handling and exceptions
   - Concurrent access (if applicable)

3. **Failure Verification**
   - Tests MUST fail when run
   - Failures for RIGHT reasons (not syntax/import errors)
   - Meaningful diagnostic error messages
   - No cascading failures

4. **Test Categories**
   - Unit: Isolated component behavior
   - Integration: Component interaction
   - Contract: API/interface contracts
   - Property: Mathematical invariants

## Framework Patterns

**JavaScript/TypeScript (Jest/Vitest)**
- Mock dependencies with `vi.fn()` or `jest.fn()`
- Use `@testing-library` for React components
- Property tests with `fast-check`

**Python (pytest)**
- Fixtures with appropriate scopes
- Parametrize for multiple test cases
- Hypothesis for property-based tests

**Go**
- Table-driven tests with subtests
- `t.Parallel()` for parallel execution
- Use `testify/assert` for cleaner assertions

**Ruby (RSpec)**
- `let` for lazy loading, `let!` for eager
- Contexts for different scenarios
- Shared examples for common behavior

## Quality Checklist

- Readable test names documenting intent
- One behavior per test
- No implementation leakage
- Meaningful test data (not 'foo'/'bar')
- Tests serve as living documentation

## Anti-Patterns to Avoid

- Tests passing immediately
- Testing implementation vs behavior
- Complex setup code
- Multiple responsibilities per test
- Brittle tests tied to specifics

## Edge Case Categories

- **Null/Empty**: undefined, null, empty string/array/object
- **Boundaries**: min/max values, single element, capacity limits
- **Special Cases**: Unicode, whitespace, special characters
- **State**: Invalid transitions, concurrent modifications
- **Errors**: Network failures, timeouts, permissions

## Output Requirements

- Complete test files with imports
- Documentation of test purpose
- Commands to run and verify failures
- Metrics: test count, coverage areas
- Next steps for green phase"

## Validation

After generation:
1. Run tests - confirm they fail
2. Verify helpful failure messages
3. Check test independence
4. Ensure comprehensive coverage

## Example (Minimal)

```typescript
// auth.service.test.ts
describe('AuthService', () => {
  let authService: AuthService;
  let mockUserRepo: jest.Mocked<UserRepository>;

  beforeEach(() => {
    mockUserRepo = { findByEmail: jest.fn() } as any;
    authService = new AuthService(mockUserRepo);
  });

  it('should_return_token_when_valid_credentials', async () => {
    const user = { id: '1', email: 'test@example.com', passwordHash: 'hashed' };
    mockUserRepo.findByEmail.mockResolvedValue(user);

    const result = await authService.authenticate('test@example.com', 'pass');

    expect(result.success).toBe(true);
    expect(result.token).toBeDefined();
  });

  it('should_fail_when_user_not_found', async () => {
    mockUserRepo.findByEmail.mockResolvedValue(null);

    const result = await authService.authenticate('none@example.com', 'pass');

    expect(result.success).toBe(false);
    expect(result.error).toBe('INVALID_CREDENTIALS');
  });
});
```

Test requirements: $ARGUMENTS

## Limitations
- Use this skill only when the task clearly matches the scope described above.
- Do not treat the output as a substitute for environment-specific validation, testing, or expert review.
- Stop and ask for clarification if required inputs, permissions, safety boundaries, or success criteria are missing.