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Testing

Testing checks whether software behaves as expected.

What Is Testing​

Tests can verify small functions, components, APIs, workflows, integrations, and full user journeys.

They help prevent regressions and make changes safer.

How To Use Testing​

Write tests around important behavior, run them automatically, and keep them clear enough to explain what the system should do.

Basic Example​

function add(a: number, b: number) {
  return a + b;
}

test("adds two numbers", () => {
  expect(add(2, 3)).toBe(5);
});

Common Concepts​

  • Unit tests check small pieces.
  • Integration tests check connected pieces.
  • End-to-end tests check real user flows.
  • Test fixtures set up known data.

What To Learn Next​

Learn assertions, mocks, fixtures, test coverage, browser testing, API testing, and continuous integration.