@Override
  public User registerUser(User userToRegister) {
    if (userToRegister == null) {
      throw new RuntimeException("invalid parameter");
    }
    validateUser(userToRegister);
    users.put(userToRegister.getUsername(), userToRegister);
    return userToRegister;
  }
Just a simple service for handling user registration and sign in.

@author ddary
selendroid-test-app/src/main/java/io/selendroid/testapp/services/impl/UserServiceImpl.java