Test Cases Generator

# Test Cases Generator

This skill generates comprehensive, requirement-driven test cases from PRD documents or user requirements.

## Purpose

Transform product requirements into structured test cases that ensure complete coverage of functionality, edge cases, error scenarios, and state transitions. The skill follows a pragmatic testing philosophy: test what matters, ensure every requirement has corresponding test coverage, and maintain test quality over quantity.

## When to Use

Trigger this skill when:
- User provides a PRD or requirements document and requests test cases
- User asks to "generate test cases", "create test scenarios", or "plan QA"
- User mentions testing coverage for a feature or requirement
- User needs structured test documentation in markdown format

## Core Testing Principles

Follow these principles when generating test cases:

1. **Requirement-driven, not implementation-driven** - Test cases must map directly to requirements, not implementation details
2. **Complete coverage** - Every requirement must have at least one test case covering:
   - Happy path (normal use cases)
   - Edge cases (boundary values, empty inputs, max limits)
   - Error handling (invalid inputs, failure scenarios, permission errors)
   - State transitions (if stateful, cover all valid state changes)
3. **Clear and actionable** - Each test case must be executable by a QA engineer without ambiguity
4. **Traceable** - Maintain clear mapping between requirements and test cases

## Workflow

### Step 1: Gather Requirements

First, identify the source of requirements:

1. If user provides a file path to a PRD, read it using the Read tool
2. If user describes requirements verbally, capture them
3. If requirements are unclear or incomplete, use AskUserQuestion to clarify:
   - What are the core user flows?
   - What are the acceptance criteria?
   - What are the edge cases or error scenarios to consider?
   - Are there any state transitions or workflows?
   - What platforms or environments need testing?

### Step 2: Extract Test Scenarios

Analyze requirements and extract test scenarios:

1. **Functional scenarios** - Normal use cases from requirements
2. **Edge case scenarios** - Boundary conditions, empty states, maximum limits
3. **Error scenarios** - Invalid inputs, permission failures, network errors
4. **State transition scenarios** - If the feature involves state, map all transitions

For each requirement, identify:
- Preconditions (what must be true before testing)
- Test steps (actions to perform)
- Expected results (what should happen)
- Postconditions (state after test completes)

### Step 3: Structure Test Cases

Organize test cases using this structure:

```markdown
# Test Cases: [Feature Name]

## Overview
- **Feature**: [Feature name]
- **Requirements Source**: [PRD file path or description]
- **Test Coverage**: [Summary of what's covered]
- **Last Updated**: [Date]

## Test Case Categories

### 1. Functional Tests
Test cases covering normal user flows and core functionality.

#### TC-F-001: [Test Case Title]
- **Requirement**: [Link to specific requirement]
- **Priority**: [High/Medium/Low]
- **Preconditions**:
  - [Condition 1]
  - [Condition 2]
- **Test Steps**:
  1. [Step 1]
  2. [Step 2]
  3. [Step 3]
- **Expected Results**:
  - [Expected result 1]
  - [Expected result 2]
- **Postconditions**: [State after test]

### 2. Edge Case Tests
Test cases covering boundary conditions and unusual inputs.

#### TC-E-001: [Test Case Title]
[Same structure as above]

### 3. Error Handling Tests
Test cases covering error scenarios and failure modes.

#### TC-ERR-001: [Test Case Title]
[Same structure as above]

### 4. State Transition Tests
Test cases covering state changes and workflows (if applicable).

#### TC-ST-001: [Test Case Title]
[Same structure as above]

## Test Coverage Matrix

| Requirement ID | Test Cases | Coverage Status |
|---------------|------------|-----------------|
| REQ-001 | TC-F-001, TC-E-001 | ✓ Complete |
| REQ-002 | TC-F-002 | ⚠ Partial |

## Notes
- [Any additional testing considerations]
- [Known limitations or assumptions]
```

### Step 4: Generate Test Cases

For each identified scenario, create a detailed test case following the structure above. Ensure:

1. **Unique IDs** - Use prefixes: TC-F (functional), TC-E (edge), TC-ERR (error), TC-ST (state)
2. **Clear titles** - Descriptive titles that explain what's being tested
3. **Requirement traceability** - Link each test case to specific requirements
4. **Priority assignment** - Mark critical paths as High priority
5. **Executable steps** - Steps must be clear enough for any QA engineer to execute
6. **Measurable results** - Expected results must be verifiable

### Step 5: Validate Coverage

Before finalizing, verify:

1. Every requirement has at least one test case
2. Happy path is covered for all user flows
3. Edge cases are identified for boundary conditions
4. Error scenarios are covered for failure modes
5. State transitions are tested if feature is stateful

If coverage gaps exist, generate additional test cases.

### Step 6: Output Test Cases

Write the test cases to `tests/<name>-test-cases.md` where `<name>` is derived from:
- The feature name from the PRD
- The user's specified name
- A sanitized version of the requirement title

Use the Write tool to create the file with the structured test cases.

### Step 7: Summary

After generating test cases, provide a brief summary in Chinese:
- Total number of test cases generated
- Coverage breakdown (functional, edge, error, state)
- Any assumptions made or areas needing clarification
- File path where test cases were saved

## Quality Checklist

Before finalizing test cases, verify:

- [ ] Every requirement has corresponding test cases
- [ ] Happy path scenarios are covered
- [ ] Edge cases include boundary values, empty inputs, max limits
- [ ] Error handling covers invalid inputs and failure scenarios
- [ ] State transitions are tested if applicable
- [ ] Test case IDs are unique and follow naming convention
- [ ] Test steps are clear and executable
- [ ] Expected results are measurable and verifiable
- [ ] Coverage matrix shows complete coverage
- [ ] File is written to tests/<name>-test-cases.md

## Example Usage

**User**: "Generate test cases for the user authentication feature in docs/auth-prd.md"

**Process**:
1. Read docs/auth-prd.md
2. Extract requirements: login, logout, password reset, session management
3. Identify scenarios: successful login, invalid credentials, expired session, etc.
4. Generate test cases covering all scenarios
5. Write to tests/auth-test-cases.md
6. Summarize coverage in Chinese

## References

For detailed testing methodologies and best practices, see:
- `references/testing-principles.md` - Core testing principles and patterns