Mocha dynamic test generation with dynamic data generation

Question

I have created a method called testLoginFailed

let testloginFailed = (app, title, data) => {
  it(title, function (done) {
    request(app)
      .post(apiEndPoints.auth.login)
      .send(data)
      .then((response) => {
        response.statusCode.should.equal(401);
        response.body.error.name.should.equal('Error');
        response.body.error.message.should.equal('login failed');
        response.body.error.code.should.equal('LOGIN_FAILED');
        done();
      })
      .catch((error) => {
        done(error);
      });
  });
};

and here is my describe block

describe('login negative Tests', () => {
before(function () {
    let loginFailedTests = [
        {
            title: 'it should fail user login using mobile because of incorrect mobile',
            data: {
                username: '1223334444',
                password: options.user.password
            }
        }, {
            title: 'it should fail user login using mobile because of incorrect password',
            data: {
                username: options.user.mobileNumber,
                password: options.user.password + '123'
            }
        }
    ];
});

loginFailedTests.forEach((test) => {
    testloginFailed(app, test.title, test.data);
});

});

Problem Statment:

1. I want to generate dynamic test cases using the function 'testloginFailed' described above.
2. So I am calling the method in a loop with different test data set testloginFailed .
3. The array testloginFailed is getting initialized in the before block as it needs some data which is in glocal scope using options.

Issue: When I am trying to use this array testloginFailed in step 2 above, it says

 loginFailedTests.forEach((test) => { ^

ReferenceError: loginFailedTests is not defined

Answer 1

From the doc RUN CYCLE OVERVIEW .

8. When a test file is loaded, Mocha executes all of its suites and finds–but does not execute–any hooks and tests therein.

11. Any “before all” hooks (for the root suite, this only happens once; see root hook plugins)

We know that the describe() and its callback will be executed before the before hook. The order of execution is describe() => before() => it()

So you should put the initialization process of test data in describe() block.

Eg

const { expect } = require('chai');
const options = { user: { password: '123', mobileNumber: '321' } };
const app = {};

let testloginFailed = (app, title, data) => {
  it(title, function () {
    expect(1 + 1).to.be.eql(2);
  });
};

describe('login negative Tests', () => {
  let loginFailedTests = [
    {
      title: 'it should fail user login using mobile because of incorrect mobile',
      data: {
        username: '1223334444',
        password: options.user.password,
      },
    },
    {
      title: 'it should fail user login using mobile because of incorrect password',
      data: {
        username: options.user.mobileNumber,
        password: options.user.password + '123',
      },
    },
  ];

  loginFailedTests.forEach((test) => {
    testloginFailed(app, test.title, test.data);
  });
});

test result:

  login negative Tests
    ✓ it should fail user login using mobile because of incorrect mobile
    ✓ it should fail user login using mobile because of incorrect password


  2 passing (5ms)