Unit Testing

Structure (Arrange-Act-Assert)

describe('ServiceName', () => {
  it('should [expected behavior] when [condition]', () => {
    // Arrange: setup
    // Act: call function
    // Assert: verify result
  });
});

What to Test

• Happy path (normal operation)
• Edge cases (empty, null, boundary values)
• Error cases (invalid input, network failure)
• Business logic (calculations, transformations)