jest-each

A parameterised testing library for Jest inspired by mocha-each.

jest-each allows you to provide multiple arguments to your test which results in the test being run once per row of parameters.

Features

• Parameterised test data
• Unique test titles with: sprintf
• Supports test.skip to skip the parameterised tests
• Supports test.only to only run the parameterised tests
• Supports asynchronous tests with done

Installation

npm i --save-dev jest-each

yarn add -D jest-each

Importing

jest-each is a default export so it can be imported with whatever name you like.

// es6
import each from 'jest-each';

// es5
const each = require('jest-each');

API

each([parameters]).test(title, testCallback)

each:

• parameters: Array the arguments that are passed into the testCallback

.test:

• title: String the title of the test, use %s in the title string to positionally inject parameter values into the test title
• testCallback: Function the test logic, this is the function that will receive the parameters as function arguments

Usage

.test

import each from 'jest-each';
import add from './add';

each([
  [1, 1, 2],
  [1, 2, 3],
  [2, 1, 3],
]).test('returns the result of adding %s to %s', (a, b, expected) => {
  expect(add(a, b)).toBe(expected);
});

.test.only

each([ [1, 1, 2] ]).test.only('returns the result of adding %s to %s', (a, b, expected) => {
  expect(add(a, b)).toBe(expected);
});

.test.skip

each([ [1, 1, 2] ]).test.skip('returns the result of adding %s to %s', (a, b, expected) => {
  expect(add(a, b)).toBe(expected);
});

asynchronous .test

each([
  ['hello'],
  ['mr'],
  ['spy'],
]).test('gives 007 secret message ', (str, done) => {
  const asynchronousSpy = (message) => {
    expect(message).toBe(str);
    done();
  };
  callSomeAsynchronousFunction(asynchronousSpy)(str);
});

License

MIT