spect_text_example.rb

```
require 'rails_helper'

RSpec.describe Admin::CoursesController, type: :controller do

  let(:valid_attributes) {
    attributes_for(:course)
  }

  let(:invalid_attributes) {
    attributes_for(:course, title: nil)
  }

  let(:valid_session) { {} }

  describe 'GET #index' do
    it "assigns all courses as @course" do
      course = Course.create! valid_attributes
      get :index, {}, valid_session
      expect(assigns(:courses)).to eq([course])
    end
  end

  describe "GET #new" do
    it "assigns a new Course as @course" do
      get :new, {}, valid_session
      expect(assigns(:course)).to be_a_new(Course)
    end
  end

  describe "GET #show" do
    it "assigns the requested course as @course" do
      course = Course.create! valid_attributes
      get :show, {:id => course.to_param}, valid_session
      expect(assigns(:course)).to eq(course)
    end
  end

  describe 'POST #create' do
    context "with valid params" do
      it "create a course" do
        expect {
          post :create, {:course => valid_attributes}, valid_session
        }.to change(Course, :count).by(1)
      end
      it "assigns a newly created Course as @course" do
        post :create, {:course => valid_attributes}, valid_session
        expect(assigns(:course)).to be_a(Course)
        expect(assigns(:course)).to be_persisted
      end

      it "redirects to the created course" do
        post :create, {:course => valid_attributes}, valid_session
        expect(response).to redirect_to([:admin, Course.last])
      end
    end

    context "with invalid params" do
      it "assigns a newly created but unsaved @course as @course" do
        post :create, {:course => invalid_attributes}, valid_session
        expect(assigns(:course)).to be_a_new(Course)
      end

      it "re-renders the 'new' template" do
        post :create, {:course => invalid_attributes}, valid_session
        expect(response).to render_template("new")
      end
    end
  end

  describe 'PUT #update' do
    context 'with valid params' do
      let(:new_attributes) {
        { title: 'Título alterado' }
      }

      it "updates the requested course" do
        course = Course.create! valid_attributes
        put :update, {:id => course.to_param, :course => new_attributes}, valid_session
        course.reload
        expect(course.title).to eq('Título alterado')
      end

      it "assigns the requested course to @course" do
        course = Course.create! valid_attributes
        put :update, {:id => course.to_param, :course => new_attributes}, valid_session
        expect(assigns(:course)).to eq(course)
      end

      it "redirects to the edit page for requested course" do
        course = Course.create! valid_attributes
        put :update, { id: course.to_param, course: new_attributes}, valid_session
        course.reload
        expect(response).to redirect_to edit_admin_course_path(course)
      end
    end

    context 'with invalid params' do
      it "assigns the course as @course" do
        course = Course.create! valid_attributes
        put :update, { id: course.to_param, course: invalid_attributes }, valid_session
        expect(assigns(:course)).to eq(course)
      end

      it "re-renders the 'edit' template" do
        course = Course.create! valid_attributes
        put :update, { id: course.to_param, course: invalid_attributes }, valid_session
        expect(response).to render_template(:edit)
      end
    end
  end

  describe "DELETE #destroy" do
    it "destroys the requested course" do
      course = Course.create! valid_attributes
      expect {
        delete :destroy, {:id => course.to_param}, valid_session
      }.to change(Course, :count).by(-1)
    end

    it "redirects to the courses list" do
      course = Course.create! valid_attributes
      delete :destroy, {:id => course.to_param}, valid_session
      expect(response).to redirect_to(admin_courses_path)
    end
  end
end

```