node mocha tests on JWT protected routes with multiple users

I am trying to test protected routes with multiple users (I'll check later resources authorisations) It' s fine when I start testing with one user , setting & saving the user in the before() hook, but as soon as I set and save a second user in this hook , then all my tests are not passing... It seems the second user setup is changing something with JWT .. ?

const rootUser = new User({
  username: config.mongo.user,
  password: config.mongo.pwd,
  email: 'johndoe@example.com',
  mobileNumber: 123456789
});
let rootJwtToken = '';

/**
 * root level hooks
 */

before(() =>
  rootUser.save({})
    .then((savedRootUser) => {
      const rootToken = jwt.sign({ username: savedRootUser.username }, config.jwtSecret);
      rootJwtToken = `Bearer ${rootToken}`;
    })
);

after(() => {
  User.remove(() => {});
  Group.remove(() => {});
  // required because https://github.com/Automattic/mongoose/issues/1251#issuecomment-65793092
  mongoose.models = {};
  mongoose.modelSchemas = {};
  mongoose.connection.close();
});

describe('## root user w Group APIs', () => {
  let group = {
    name: 'Admin',
    description: 'Administration group'
  };

  describe('# POST /api/v1/groups', () => {
    it('should allow root user to create a new group', () =>
      request(app)
        .post('/api/v1/groups')
        .set('Authorization', rootJwtToken)
        .send(group)
        .expect(httpStatus.OK)
        .then((res) => {
          // check group
          expect(res.body.name).to.equal(group.name);
          expect(res.body.description).to.equal(group.description);
          group = res.body;
        })
    );
  });
  describe('# DELETE /api/v1/groups/:groupId', () => {
    it('should allow root user to delete a group', () =>
      request(app)
        .delete(`/api/v1/groups/${group._id}`)
        .set('Authorization', rootJwtToken)
        .expect(httpStatus.OK)
        .then((res) => {
          expect(res.body.name).to.equal('Administrator');
        })
    );
  });
});

Then I test after adding another user

const rootUser = new User({
  username: config.mongo.user,
  password: config.mongo.pwd,
  email: 'johndoe@example.com',
  mobileNumber: 123456789
});
let rootJwtToken = '';

const adminUser = new User({
  username: cadminuser',
  password: '999999999,
  email: 'william@example.com',
  mobileNumber: 97654321
});
let adminwtToken = '';


/**
 * root level hooks
 */

before(() => {
  rootUser.save({})
    .then((savedRootUser) => {
      const rootToken = jwt.sign({ username: savedRootUser.username }, config.jwtSecret);
      rootJwtToken = `Bearer ${rootToken}`;
    });
  adminUser.save({})
    .then((savedAdminUser) => {
      const adminToken = jwt.sign({ username: savedAdminUser.username }, config.jwtSecret);
      adminJwtToken = `Bearer ${adminToken}`;
    });
});

....
describe('## root user w Group APIs', () => {
...using rootJwtToken
}
describe('## admin user w Group APIs', () => {
...using adminJwtToken
}

thanks for your feedbacks

via erwin