@Test
public void managerWithFiveSubordinatesHasFavoriteEmployee() {
  Employee manager = createEmployee(JobTitle.MANAGER);
  manager.subordinates = RandomCollectionUtils.randomListFrom(this::createSubordinate, 5);
  Employee favoriteEmployee = IterableUtils.randomFrom(manager.subordinates);
  assertTrue(manager.subordinates.contains(favoriteEmployee));
}

private Employee createEmployee(JobTitle jobTitle) {
  Employee employee = new Employee();
  employee.jobTitle = jobTitle;
  employee.birthDateTime = RandomDateUtils.randomPastZonedDateTime();
  employee.startDate = RandomDateUtils.randomLocalDate();
  employee.endDate = RandomDateUtils.randomLocalDateAfter(employee.startDate);
  employee.clockInTime = RandomDateUtils.randomLocalTime();
  employee.clockOutTime = RandomDateUtils.randomLocalTimeAfter(employee.clockInTime);
  employee.lunchTime = RandomDateUtils.randomLocalTime(employee.clockInTime, employee.clockOutTime);
  employee.subordinates = Collections.emptyList();
  return employee;
}

private Employee createSubordinate() {
  JobTitle[] excludes = new JobTitle[] { JobTitle.MANAGER, JobTitle.SUPERVISOR };
  return createEmployee(RandomEnumUtils.random(JobTitle.class, excludes));
}

private class Employee {

  JobTitle jobTitle;
  ZonedDateTime birthDateTime;
  LocalDate startDate;
  LocalDate endDate;
  LocalTime clockInTime;
  LocalTime clockOutTime;
  LocalTime lunchTime;
  List<Employee> subordinates;
}

private enum JobTitle {
  MANAGER, SUPERVISOR, DEVELOPER, TESTER
}