lesson

Introduction to Testing

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35 minlesson

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1 min read

Introduction to Testing

Testing verifies that your code works as expected. Unit tests check individual functions in isolation using assertions like expect(actual).toBe(expected).

Jest Basics

describe groups related tests
it defines a single test
expect(...).toBe(...) asserts equality

Example

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

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

Your Task

Add a third test case for the add function, then run the test suite.

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

Introduction to Testing

Testing verifies that your code works as expected. Unit tests check individual functions in isolation using assertions like expect(actual).toBe(expected).

Jest Basics

describe groups related tests
it defines a single test
expect(...).toBe(...) asserts equality

Example

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

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

Your Task

Add a third test case for the add function, then run the test suite.

1 min read

Introduction to Testing

Testing verifies that your code works as expected. Unit tests check individual functions in isolation using assertions like expect(actual).toBe(expected).

Jest Basics

describe groups related tests
it defines a single test
expect(...).toBe(...) asserts equality

Example

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

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

Your Task

Add a third test case for the add function, then run the test suite.

1 min read

Introduction to Testing

Testing verifies that your code works as expected. Unit tests check individual functions in isolation using assertions like expect(actual).toBe(expected).

Jest Basics

describe groups related tests
it defines a single test
expect(...).toBe(...) asserts equality

Example

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

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

Your Task

Add a third test case for the add function, then run the test suite.