ActionView :: Template :: Error中的黄瓜路由结果

Question

所以我正在尝试设置一个黄瓜测试，访问将访问课程索引页面，然后点击一个课程去特定课程的显示页面。然而，最终发生的事情是，一切都按预期进行（在课程控制器中点击show动作，显示正确的@student对象，一旦路径被激活它应该重定向到），但它实际上不会这样做。它会命中课程控制器，并导致No route matches {:action=>"show", :controller=>"courses", :id=>nil} missing required keys: [:id] (ActionView::Template::Error)错误消息。

这是我的设置：

admin_view_steps.rb

When(/^I select a student$/) do
  click_on "#{@student.first_name} #{@student.last_name}"
end

Then(/^I should see their information$/) do
  expect(page).to have_content(@student.first_name)
end

admin_view.feature

Scenario: See Individual Student Page
    Given I am logged in as a flatiron employee
    When  I visit the students page
    And   I select a student
    Then  I should see their information

courses_controller.rb

class CoursesController < ApplicationController
  def index
    @courses = Course.all
  end

  def new
    @course = Course.new
  end

  def create
    @course = Course.new(course_params)
    if @course.save
      flash[:notice] = "Course has successfully been saved."
      redirect_to course_path(@course)
    else
      flash[:notice] = "Error! Course was not successfully saved."
      redirect to new_course_path
    end
  end

  def show
    @course = Course.find(params[:id])
  end

  private

  def course_params
    params.require(:course).permit(:name)
  end
end

students_controller.rb

class StudentsController < ApplicationController
  before_filter :set_student, only: [:show, :edit, :update, :destroy]

  def index
    @students = Student.all
  end

  def show
  end

  def new
    @student = Student.new
  end

  def edit
  end

  def create
    @student = Student.new(student_params)
    if @student.save
      flash[:notice] = "Student form successfully submitted."
      redirect_to students_path
    else
      flash[:error] = "Unable to process your request."
      render :new
    end
  end

  def update
    Student.update(@student, student_params)
    redirect_to student_path(@student)
  end

  def destroy
    @student.destroy
    redirect_to courses_path
  end

  private

  def set_student
    @student = Student.find(params[:id])
  end

  def student_params
    params.require(:student).permit(removed_attributes)
  end
end

的routes.rb

Registrar::Application.routes.draw do

  resources :courses do
    resources :students, controller: :courses_students, only: [:new, :create, :show]
  end

  resources :students

  devise_for :users, :path_names => { sign_in: 'login', sign_out: 'logout' }, :controllers => {
    :omniauth_callbacks => "users/omniauth_callbacks",
    :sessions => "sessions"
  }

    root 'pages#landing'
end

学生/ show.html.erb

<br><br>
<%= @student.first_name %>
<%= @student.last_name %><br>
<br>
<%= link_to "Back to Course", course_path(@student.course) %> 
<%= link_to "Students", students_path %>
<br>

学生/ index.html.erb

<br><br>
<% @students.each do |student| %>
  <%= link_to "#{student.first_name} #{student.last_name}", student_path(student) %><br>
<% end %>
<br>
<%= link_to "Landing Page", root_path %>

非常感谢任何帮助！