Jest Testing Patterns

Master Jest testing patterns including unit tests, mocks, spies, snapshots, and assertion techniques for comprehensive test coverage. This skill covers the fundamental patterns and practices for writing effective, maintainable tests using Jest.

Basic Test Structure

Test Suite Organization

describe('Calculator', () => {
  describe('add', () => {
    it('should add two positive numbers', () => {
      expect(add(2, 3)).toBe(5);
    });

    it('should add negative numbers', () => {
      expect(add(-2, -3)).toBe(-5);
    });