npm install --save-dev mocha
./node_modules/mocha/bin/mocha

# or if you put in package.json
# "scripts": {
#   "test": "mocha"
# }

npm test

// test/test.js
var assert = require('assert');
describe('alertTextShowHide', function() {
  describe('#elementText', function() {
    it('should show message', function() {
      assert.equal(1, 1);
    });
  });
});

npm install --save-dev sinon
# var sinon = require('sinon');

it('should call_method'), () => {
  const spy = sinon.spy(object, 'method')
  object.method(3)
  assert(spy.withArgs(3).calledOnce)
}