generateCredentials(username, password) {
  return {
    username: username,
    password: password
  };
}

describe('#generateCredentials(username, password)', function() {
    it('creates a JSON object with the passed in arguments', function() {

      var creds = generateCredentials('user', 'pass');

      var expectedCreds =  { username: 'user', password: 'pass' };

      expect(creds).to.equal(expectedCreds);
    });
  });

AssertionError: expected { username: 'user', password: 'pass' } to equal { username: 'user', password: 'pass' }