How to write a rspec test for edit user information function and change password function?

问题

Does anyone knows how can I write a rspec test for these two functions? The update function is used to allow user to edit their information and update. The second function is used to change user's password with requiring user's old password.

def update
  @user = current_user
  if @user.update_attributes(user_params)
    head :no_content
  else 
    render_error(:unprocessable_entity, "Failed to update information")
  end
end

def change_password
  @user = current_user
  if @user.authenticate(params[:password])
    @user.update_attributes({:password => params[:password]})
    head :no_content
  else
    render_error(:unprocessable_entity, "Wrong Password!")
  end  
end  

来源：https://stackoverflow.com/questions/47357256/how-to-write-a-rspec-test-for-edit-user-information-function-and-change-password