test-generator

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name: Test Generator description: Generate comprehensive unit tests for functions and classes. allowed-tools: Read, Write, Shell

Test Generator Skill

Generate high-quality unit tests that maximize coverage and confidence in the codebase.

Test Generation Strategies

1. Input Partitioning: Identify equivalence classes and boundary values. Test empty inputs, single items, max-size collections, and invalid types.

2. State Coverage: For stateful objects, test initialization, transitions, and terminal states. Cover happy path and all error branches.

3. Mocking Patterns: Mock external dependencies (HTTP, DB, file system) at boundaries. Use dependency injection to enable test doubles. Avoid over-mocking; prefer real objects for pure logic.

4. Assertions: Use descriptive assertion messages. Prefer specific matchers (e.g., toThrowWithMessage) over generic ones. Assert on observable behavior, not implementation details.

Coverage Targets

• Aim for 80%+ line coverage on business logic; 100% on critical paths (auth, payments, data integrity).
• Prioritize branch coverage over line coverage for complex conditionals.
• Use Read to understand the function/class under test, Write to create test files, and Shell to run the test suite and verify results.

Output Format

• Place tests in the project's standard test directory (e.g., tests/, __tests__/, *.test.ts).
• Follow existing test naming and structure conventions.
• Include setup/teardown where needed and ensure tests are isolated and repeatable.