rspec-should_receive.rb

    describe CoursesController, "POST /my/courses #create" do

      before(:each) do
        @valid_course_attributes = { :name => '7C', :subject => 'Philosophie', :school_year => '2010-2011' }.stringify_keys
        @new_course = Course.make_unsaved(@valid_course_attributes)
      end

      def do_post
        post :create, :course => @valid_course_attributes
      end

      it "should build the new course" do
        @teacher.courses.should_receive(:build).with(@valid_course_attributes).and_return(@new_course)
        @new_course.should_receive(:save).and_return(true)
        do_post
      end

      it "should redirect back to the courses page" do
        do_post
        response.should redirect_to(my_courses_path)
      end

    end