Scaffold Tests

Scaffold Tests

Use this skill to automatically generate test suites for your code, ensuring functionality is locked in.

Inputs

• Target File: The source code specific to test.
• Test Runner: (Optional) Jest, Pytest, etc.

Tooling Strategy

• Use view_file to analyze the source code.
• Use write_to_file to create the test file.

Workflow

1. Context Analysis

• Target: Analyze the open file or the specified module (e.g., utils.py, auth.js).
• Framework Detection: Determine the project's test runner (Jest, PyTest, Mocha, Unittest). If none, suggest the most lightweight option suitable for the user's legacy hardware.

2. Test Strategy

Plan the test coverage:

• Unit Tests: Isolated tests for individual functions/classes.
• Regression Tests: Tests that ensure specific bugs (fixes) don't reappear.
• Naming Convention: Standardize names (e.g., [filename].test.js or test_[filename].py).

3. Generation (The "Safety Net")

Write the test file with three specific sections:

• Happy Path: Standard inputs produce standard outputs (The "It works" check).
• Edge Cases: Nulls, empty strings, zeros, huge numbers (The "Robustness" check).
• Error Handling: Invalid inputs trigger the expected error messages (The "Security" check).

4. Output

• Save the file to a tests/ directory or alongside the source code (based on project convention).
• Prompt the user to run them using /run_tests.

Advanced Testing Patterns

• Test-Driven Development (TDD): Write failing test FIRST, implement minimal code to pass, refactor after green. Never write production code without a failing test.
• Behavior-Driven Testing: Test behavior, not implementation details. Focus on public APIs and business requirements. Use descriptive test names that describe the behavior.
• Factory Pattern: When scaffolding tests, create data factory functions (e.g., getMockUser(overrides)) that provide sensible defaults but allow tests to override specific properties. This keeps tests DRY and maintainable.
• Mocking Strategies: Use factory functions to mock entire modules or specific hooks when scaffolding tests to isolate the unit under test.