testing-strategies

Universal Testing Strategies

Overview

Language-agnostic testing patterns and strategies applicable across all technology stacks.

Testing Pyramid

          ┌───────┐
          │  E2E  │  Few, slow, expensive
         ─┴───────┴─
        ┌───────────┐
        │Integration│  Some, medium speed
       ─┴───────────┴─
      ┌───────────────┐
      │     Unit      │  Many, fast, cheap
     ─┴───────────────┴─

Unit Tests (70-80%)

• Test individual functions/methods in isolation
• Mock external dependencies
• Fast execution (< 10ms per test)
• High volume, run on every save

Integration Tests (15-20%)

• Test component interactions
• Real database/API calls (often with test containers)
• Medium speed (100ms - 1s per test)
• Run on commit/PR

End-to-End Tests (5-10%)

• Test complete user flows
• Real browser/environment
• Slow (seconds to minutes)
• Run before deployment

Test Structure: AAA Pattern

// Arrange - Set up test data and conditions
const user = createTestUser({ email: '[email protected]' });
const service = new UserService(mockDb);

// Act - Execute the code under test
const result = await service.createUser(user);

// Assert - Verify the expected outcome
expect(result.id).toBeDefined();
expect(result.email).toBe('[email protected]');

Naming Conventions

Test File Names

component.test.ts       # Unit tests
component.spec.ts       # Alternative convention
component.integration.ts # Integration tests
component.e2e.ts        # End-to-end tests

Test Case Names

Use descriptive names that explain the scenario:

// Pattern: should [expected behavior] when [condition]
describe('UserService', () => {
  describe('createUser', () => {
    it('should create user when valid data provided', () => {});
    it('should throw ValidationError when email is invalid', () => {});
    it('should throw DuplicateError when email already exists', () => {});
  });
});

BDD Style (Given-When-Then)

describe('User Registration', () => {
  describe('given a valid email and password', () => {
    describe('when the user submits the form', () => {
      it('then creates a new account', () => {});
      it('then sends a welcome email', () => {});
    });
  });
});