Test Plan Generator Skill

Purpose

Analyze implementation changes and generate comprehensive, non-redundant test plans that provide appropriate coverage without over-testing. Works with any language, framework, or architecture by analyzing change patterns rather than specific technologies.

When to Use This Skill

Use this skill when:

• Feature implementation is complete
• Need to generate test plan for changes
• Want to ensure proper test coverage
• Need to avoid redundant tests
• Want to balance thoroughness with efficiency
• Creating test plan for test-executor to run

Test Plan Generation Workflow

Phase 1: Analyze Changes

1. Identify Changed Files

   git diff main...HEAD --name-only
   # or
   git diff <base-branch>...HEAD --name-only
   

2. Analyze Change Types

   • New files vs modified files
   • Backend vs frontend vs database
   • API endpoints vs UI components
   • Configuration vs logic

3. Read Implementation

   • Understand what was implemented
   • Identify critical paths
   • Determine user-facing changes
   • Note performance-sensitive areas

Phase 2: Determine Test Types Needed

Based on changes, identify which test types are appropriate:

API Endpoint Added/Modified → API Tests

When:

• New REST/GraphQL endpoints
• Modified endpoint behavior
• Changed request/response format

Tests:

• Request validation
• Response format
• Success scenarios
• Error scenarios (400, 401, 403, 404, 500)
• Edge cases

Skip E2E if: API is internal only (not user-facing)

UI Component Added/Modified → E2E Tests

When:

• New pages or components
• Modified user flows
• Changed UI behavior

Tests:

• User interaction flows
• Form submissions
• Navigation
• Visual feedback

Skip API tests if: E2E tests already cover backend through UI

Database Schema Changed → Migration Tests

When:

• New tables/columns
• Modified schema
• Data migrations

Tests:

• Migration up/down
• Data integrity
• Foreign key constraints
• Indexes applied

Business Logic Added → Unit Tests

When:

• Complex algorithms
• Validation logic
• Calculations
• Data transformations

Tests:

• Valid inputs
• Invalid inputs
• Edge cases
• Error handling

Consider skipping if: Logic is tested adequately by integration/E2E tests

Performance-Critical Code → Performance Tests

When:

• Database queries
• Large data processing
• API endpoints with latency requirements
• File operations

Tests:

• Response time under load
• Resource usage
• Scalability
• Throughput

Phase 3: Avoid Redundant Tests

Key Principle: Don't test the same thing twice at different levels.

Example: Form Submission Feature

Backend API:

• Endpoint: POST /api/forms
• Logic: Validation, database insert, email notification

Frontend:

• Component: FormBuilder
• User flow: Fill form → Submit → Success message

Test Strategy:

✅ Good (Non-Redundant):

## E2E Tests
- [ ] User can create form, fill details, and submit successfully
- [ ] User sees error message for invalid email
- [ ] User sees success confirmation after submission

## API Tests (only edge cases not covered by E2E)
- [ ] API returns 400 for malformed JSON
- [ ] API handles concurrent submissions correctly

## Unit Tests (complex logic not easily tested via E2E)
- [ ] SIRET validation algorithm works correctly

❌ Bad (Redundant):

## E2E Tests
- [ ] User can submit form

## API Tests (redundant with E2E)
- [ ] POST /api/forms creates form in database
- [ ] POST /api/forms returns 200 on success
- [ ] POST /api/forms validates email format

## Unit Tests (redundant with E2E and API)
- [ ] FormController.Create method works
- [ ] Email validation works

Redundancy: E2E test already covers API behavior and validation through UI. No need for separate API tests unless testing edge cases not accessible via UI.

Phase 4: Generate Test Plan Document

Create test-plan.md with structure:

# Test Plan: [Feature Name]

**Date:** [Date]
**Implementation:** [Branch/PR]

## Overview
[Brief description of what was implemented]

## Changed Files
- `path/to/file1.ts`
- `path/to/file2.cs`

## Test Strategy
[Explanation of test approach and coverage]

---

## E2E Tests (Priority: High)

- [ ] Test 1: [Description]
- [ ] Test 2: [Description]

---

## API Tests (Priority: Medium)

- [ ] Test 1: [Description]
- [ ] Test 2: [Description]

---

## Unit Tests (Priority: Low)

- [ ] Test 1: [Description]
- [ ] Test 2: [Description]

---

## Performance Tests (Optional)

- [ ] Test 1: [Description]

---

## Notes
[Any important testing considerations]

Test Type Guidelines

E2E (End-to-End) Tests

Purpose: Test complete user flows from UI to backend

When to Include:

• User-facing features
• Critical workflows
• Multi-step processes
• Integration between frontend and backend

Example Tests:

- [ ] User can register, login, and access dashboard
- [ ] User can create form with all field types
- [ ] User can submit form and see confirmation
- [ ] Admin can view all submissions for a form

How to Execute: Browser automation (Playwright, Cypress, etc.)

API Tests

Purpose: Test backend endpoints directly

When to Include:

• Endpoints not fully covered by E2E
• Edge cases difficult to test via UI
• Error scenarios (400, 401, 500)
• API-only features (webhooks, batch operations)

Example Tests:

- [ ] POST /api/forms returns 400 for invalid JSON
- [ ] GET /api/forms?page=999 handles non-existent page
- [ ] PUT /api/forms/{id} returns 404 for non-existent form
- [ ] API rate limiting works (429 after 100 requests/min)

How to Execute: curl, httpie, or API test framework

Unit Tests

Purpose: Test individual functions/methods in isolation

When to Include:

• Complex algorithms (validation, calculations)
• Business logic that's hard to test at higher levels
• Utility functions
• Edge cases in isolated functions

Example Tests:

- [ ] ValidateSIRET returns true for valid SIRET
- [ ] ValidateSIRET returns false for invalid checksum
- [ ] CalculatePrice handles discount correctly
- [ ] ParseDate handles multiple date formats

How to Execute: Test framework (Jest, xUnit, pytest, etc.)

Skip if: Logic is adequately covered by integration or E2E tests

Integration Tests

Purpose: Test interactions between components

When to Include:

• Database operations
• External API integrations
• Service-to-service communication
• File operations

Example Tests:

- [ ] User creation persists to database correctly
- [ ] Email service integrates with Microsoft Graph API
- [ ] File upload saves file and creates database record
- [ ] Redis caching works with API queries

How to Execute: Test framework with real dependencies (or test doubles)

Performance Tests

Purpose: Test speed, scalability, resource usage

When to Include:

• Performance-critical features
• Database queries on large datasets
• APIs with latency requirements
• Batch operations

Example Tests:

- [ ] GET /api/submissions returns in <200ms with 10,000 records
- [ ] File upload handles 100MB files without timeout
- [ ] Dashboard loads in <1s with 50 forms
- [ ] API handles 100 concurrent requests without errors

How to Execute: Load testing tools (ab, wrk, k6, JMeter)

Prioritization

High Priority (Must Test)

• Critical user flows
• Data integrity
• Security features
• Core business logic

Medium Priority (Should Test)

• Edge cases
• Error handling
• Non-critical features
• Performance benchmarks

Low Priority (Nice to Test)

• UI polish
• Minor optimizations
• Rarely-used features

Mark priorities in test plan:

## E2E Tests (Priority: High)
- [ ] 🔴 User authentication flow
- [ ] 🔴 Form submission and data persistence

## API Tests (Priority: Medium)
- [ ] 🟡 Error handling for malformed requests
- [ ] 🟡 Pagination edge cases

## Unit Tests (Priority: Low)
- [ ] 🟢 Date formatting utility
- [ ] 🟢 String truncation helper

Change Pattern Analysis

Pattern 1: New CRUD API

Changes:

• New controller with Create, Read, Update, Delete endpoints
• New entity
• New database migration

Tests Needed:

## E2E Tests
- [ ] Create resource via UI
- [ ] View resource in list
- [ ] Edit resource
- [ ] Delete resource

## API Tests (edge cases)
- [ ] POST validates required fields
- [ ] PUT returns 404 for non-existent resource
- [ ] DELETE is idempotent

Pattern 2: Complex Validation Logic

Changes:

• New validation service with business rules

Tests Needed:

## Unit Tests (thorough)
- [ ] Valid inputs pass validation
- [ ] Invalid inputs fail with correct errors
- [ ] Edge cases (boundary values, null, empty)

## Integration Tests
- [ ] Validation integrated into API correctly

Skip E2E if validation errors are covered by unit + integration tests.

Pattern 3: UI-Only Changes

Changes:

• New React components
• CSS styling updates

Tests Needed:

## E2E Tests (light)
- [ ] Component renders correctly
- [ ] User interactions work
- [ ] Responsive behavior

## Visual Regression (optional)
- [ ] Screenshot comparison tests

Skip API and unit tests (no backend changes).

Pattern 4: Database Migration

Changes:

• Schema changes
• Data migration scripts

Tests Needed:

## Migration Tests
- [ ] Migration applies successfully
- [ ] Migration rollback works
- [ ] Existing data remains intact
- [ ] New constraints are enforced

## Integration Tests
- [ ] API works with new schema

Pattern 5: Performance Optimization

Changes:

• Query optimization
• Caching added
• Indexing added

Tests Needed:

## Performance Tests
- [ ] Response time improved (before/after benchmark)
- [ ] Resource usage decreased
- [ ] Scalability improved

## Regression Tests
- [ ] Functionality unchanged (no bugs introduced)

Generic Test Generation Algorithm

def generate_test_plan(changes):
    tests = []

    # Analyze changes
    backend_changes = filter(is_backend, changes)
    frontend_changes = filter(is_frontend, changes)
    db_changes = filter(is_database, changes)

    # Determine E2E needs
    if frontend_changes or user_facing(backend_changes):
        tests.extend(generate_e2e_tests(changes))

    # Determine API needs
    if backend_changes and not fully_covered_by_e2e(backend_changes):
        tests.extend(generate_api_tests(backend_changes))

    # Determine unit test needs
    complex_logic = find_complex_logic(changes)
    if complex_logic:
        tests.extend(generate_unit_tests(complex_logic))

    # Determine integration test needs
    if db_changes or external_integrations(changes):
        tests.extend(generate_integration_tests(changes))

    # Determine performance test needs
    if is_performance_critical(changes):
        tests.extend(generate_performance_tests(changes))

    # Remove redundant tests
    tests = deduplicate(tests)

    return tests

Tips for Effective Test Plans

1. Analyze Changes First: Understand what was implemented
2. Think Coverage, Not Quantity: More tests ≠ better
3. Avoid Redundancy: Test each thing once at the right level
4. Prioritize: Mark critical tests as high priority
5. Be Specific: "Test form submission" → "Test form submission with file upload"
6. Consider Maintenance: Don't create brittle tests
7. Think User Perspective: E2E tests should match real usage
8. Document Rationale: Explain test strategy in plan
9. Balance Thoroughness: Cover important cases, skip trivial ones
10. Update as Needed: Adjust plan based on test execution results

Bundled Resources

• scripts/analyze_changes.py - Analyze git diff to determine test needs
• references/test-strategies.md - Test strategies by change type