jest-skill

name	jest-skill
description	Generates Jest unit and integration tests in JavaScript or TypeScript. Covers mocking, snapshots, async testing, and React component testing. Use when user mentions "Jest", "describe/it/expect", "jest.mock", "toMatchSnapshot". Triggers on: "Jest", "expect().toBe()", "jest.mock",...
risk	unknown
source	https://github.com/LambdaTest/agent-skills/tree/main/jest-skill
source_repo	LambdaTest/agent-skills
source_type	community
date_added	2026-07-01T00:00:00.000Z
license	MIT
license_source	https://github.com/LambdaTest/agent-skills/blob/main/LICENSE

Jest Testing Skill

When to Use

Use this skill when you need generates Jest unit and integration tests in JavaScript or TypeScript. Covers mocking, snapshots, async testing, and React component testing. Use when user mentions "Jest", "describe/it/expect", "jest.mock", "toMatchSnapshot". Triggers on: "Jest", "expect().toBe()", "jest.mock",...

Core Patterns

Basic Test

describe('Calculator', () => {
  let calc;
  beforeEach(() => { calc = new Calculator(); });

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

  test('throws on division by zero', () => {
    expect(() => calc.divide(10, 0)).toThrow('Division by zero');
  });
});

Matchers

expect(value).toBe(exact);                 // === strict
expect(value).toEqual(object);             // deep equality
expect(value).toBeTruthy();
expect(value).toBeNull();
expect(value).toBeGreaterThan(3);
expect(value).(, );
(str).();
(arr).(item);
(arr).();
(obj).();
(obj).({ :  });
( ()).();