title: NoMethodError: undefined method `deliver_now' for #<Mail::Message:0x000001058258b0> RoR
body: <p>I am running some tests in my Rails 4 application, and I am receiving the following errors:</p>
  
  <pre><code>1) Error:
  UsersLoginTest#test_valid_signup_information:
  NoMethodError: undefined method `deliver_now' for #&lt;Mail::Message:0x000001058258b0&gt;
      app/controllers/users_controller.rb:33:in `create'
      test/integration/users_login_test.rb:33:in `block (2 levels) in &lt;class:UsersLoginTest&gt;'
      test/integration/users_login_test.rb:32:in `block in &lt;class:UsersLoginTest&gt;'
  
  
    2) Error:
  UsersSignupTest#test_valid_signup_information:
  NoMethodError: undefined method `deliver_now' for #&lt;Mail::Message:0x0000010b8fa7a8&gt;
      app/controllers/users_controller.rb:33:in `create'
      test/integration/users_signup_test.rb:21:in `block (2 levels) in &lt;class:UsersSignupTest&gt;'
      test/integration/users_signup_test.rb:20:in `block in &lt;class:UsersSignupTest&gt;'
  </code></pre>
  
  <p>They both have said: undefined method `deliver_now'</p>
  
  <p>I'm not sure why this is the case.  </p>
  
  <p>app/controllers/users_controller.rb:33 -></p>
  
  <pre><code>def create
      @user = User.new(user_params)
      if @user.save
        UserMailer.account_activation(@user).deliver_now
        flash[:info] = "Please check your email to activate your account."
        redirect_to root_url
      else
        render 'new'
      end
    end
  </code></pre>
  
  <p>test/integration/users_login_test.rb:21 -></p>
  
  <pre><code>test "valid signup information" do
      get signup_path
      assert_difference 'User.count', 1 do
        post_via_redirect users_path, user: { name:  "Example User",
                                              email: "user@example.com",
                                              password:              "password",
                                              password_confirmation: "password" }
      end
      assert_template 'users/show'
      assert is_logged_in?
    end
  </code></pre>
  
  <p>Do you see the issue?</p>