ruby-on-rails – 为什么电子邮件没有进入ActionMailer :: Base.

config / environments / development.rb：config.action_mailer.delivery_method =：test.

应用程序/邮寄者/ notifier.rb

def send_email(user)
  mail(:to => user.email,:subject => "Welcome to our website!")
end

这些是我正在运行的测试：

When /^I signup$/ do
  visit signup_path
  @user = FactoryGirl.build(:user)
  fill_in "user_email",:with => @user.email
  fill_in "user_password",:with => @user.password
  click_button "Join now"
end

Then /^I should receive a confirmation email$/ do
  email = ActionMailer::Base.deliveries.last
  email.subject.should == "Welcome to our website!"
end

现在我收到以下错误,我应该收到确认电子邮件步骤：
nil的未定义方法主题：NilClass(NoMethodError)

谢谢！