lesson

Test-Driven Development

26 / 47

40 minlesson

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1 min read

Write test first (red), implement to pass (green), refactor (refactor). TDD ensures tests drive design and keep code testable.

What You'll Learn

// Red: write test first
test('factorial of 0 is 1', () => {
  expect(factorial(0)).toBe(1);
});

test('factorial of 5 is 120', () => {
// ...

You completed the free preview — you are ready for the full path.

All lessons are readable below. To write and run code from lesson 11 onwards, upgrade to Path Plus ($9/mo) or Pro.

1 min read

Write test first (red), implement to pass (green), refactor (refactor). TDD ensures tests drive design and keep code testable.

// Red: write test first
test('factorial of 0 is 1', () => {
  expect(factorial(0)).toBe(1);
});

test('factorial of 5 is 120', () => {
// ...

1 min read

Write test first (red), implement to pass (green), refactor (refactor). TDD ensures tests drive design and keep code testable.

// Red: write test first
test('factorial of 0 is 1', () => {
  expect(factorial(0)).toBe(1);
});

test('factorial of 5 is 120', () => {
// ...

1 min read

Write test first (red), implement to pass (green), refactor (refactor). TDD ensures tests drive design and keep code testable.

// Red: write test first
test('factorial of 0 is 1', () => {
  expect(factorial(0)).toBe(1);
});

test('factorial of 5 is 120', () => {
// ...