Testing

Testing Skill

When working on testing tasks, follow these guidelines:

Test Generation Approach

1. Understand the Code

• Analyze the function/module to be tested
• Identify inputs, outputs, and side effects
• Note dependencies and external interactions
• Understand the business logic and requirements

2. Test Categories

Unit Tests

• Test individual functions/methods in isolation
• Mock external dependencies
• Focus on single responsibility
• Fast execution

Integration Tests

• Test component interactions
• Use real or test doubles for dependencies
• Verify data flow between modules
• Test API endpoints with actual calls

End-to-End Tests

• Test complete user workflows
• Use real or staging environment
• Validate from user perspective
• Cover critical business paths

3. Test Coverage

Ensure tests cover:

• Happy Path: Normal, expected inputs and flows
• Edge Cases: Boundary values, empty inputs, maximum values
• Error Cases: Invalid inputs, missing data, exceptions
• State Changes: Before/after state verification
• Side Effects: Database changes, API calls, file operations

4. Test Structure (AAA Pattern)

// Arrange: Set up test data and conditions
// Act: Execute the code under test
// Assert: Verify the results

5. Best Practices

• Clear Names: Test names should describe what's being tested and expected behavior
  • Format: test_[method]_[scenario]_[expectedResult]
  • Example: test_calculateTotal_withDiscount_returnsReducedAmount
• One Assert Per Test: Each test should verify one behavior
• Independent Tests: Tests should not depend on each other
• Fast Tests: Keep unit tests fast (< 100ms)
• Reliable Tests: No flaky tests, no random data without seeds
• Maintainable: Easy to understand and update

6. Testing Frameworks

Adapt to the project's testing framework:

• JavaScript/TypeScript: Jest, Mocha, Vitest, Cypress
• Python: pytest, unittest, nose2
• Java: JUnit, TestNG, Mockito
• C#: NUnit, xUnit, MSTest
• .NET: xUnit, NUnit
• Go: testing package, testify
• Ruby: RSpec, Minitest

7. Mocking Strategy

• Mock external dependencies (APIs, databases, file system)
• Use test doubles appropriately:
  • Mocks: Verify interactions
  • Stubs: Provide predetermined responses
  • Fakes: Simplified working implementations
  • Spies: Record information about calls

8. Output Format

When generating tests, provide:

1. Test file location and name
2. Necessary imports and setup
3. Complete test cases with:
   • Descriptive names
   • Arrange/Act/Assert sections
   • Comments explaining complex scenarios
4. Coverage summary: What's tested, what's not
5. Running instructions: How to execute tests

Code Coverage Goals

• Minimum: 70% overall coverage
• Target: 80%+ for critical business logic
• Focus: Quality over quantity - meaningful tests, not just coverage numbers

When Improving Existing Tests

1. Analyze current coverage: Identify gaps
2. Review existing tests: Check for anti-patterns
3. Prioritize: Start with critical paths and low-coverage areas
4. Refactor: Make tests more maintainable
5. Document: Add comments for complex test scenarios