mocha test throw the function code example

Example 1: mocha should throw error

describe('createMap', () => {
    it('should throw an error if no contents were sent as argument', () => {
      expect(() => createMap()).to.throw('You have to send a list of things to map.');
    });
  });

Example 2: mocha js

Mocha is a JavaScript test framework!

var assert = require('assert');
describe('Array', function () {
  describe('#indexOf()', function () {
    it('should return -1 when the value is not present', function () {
      assert.equal([1, 2, 3].indexOf(4), -1);
    });
  });
});