articles_controller_spec.rb

require 'spec_helper'

describe ArticlesController do
  let(:article) { build_stubbed(:article) }

  describe 'GET #index' do
    before do
      Article.stub all: [article]
      get :index
    end

    it 'gets all articles' do
      expect(Article).to have_received(:all)
    end

    it 'assigns @articles' do
      expect(assigns(:articles)).to eq [article]
    end

    it 'responds successfully' do
      expect(response).to be_success
    end

    it 'renders :index template' do
      expect(response).to render_template(:index)
    end
  end

  describe 'GET #show' do
    before do
      Article.stub find: article
      get :show, id: article
    end

    it 'finds article by id' do
      expect(Article).to have_received(:find).with(article.id.to_s)
    end

    it 'assigns @article' do
      expect(assigns(:article)).to eq(article)
    end

    it 'responds successfully' do
      expect(response).to be_success
    end

    it 'renders :show template' do
      expect(response).to render_template(:show)
    end
  end

  describe 'GET #new' do
    let(:new_article) { mock_model(Article) }

    before do
      Article.stub new: new_article
      get :new
    end

    it 'builds new article' do
      expect(Article).to have_received(:new)
    end

    it 'assigns new article to @article' do
      expect(assigns(:article)).to eq(new_article)
    end

    it 'responds successfully' do
      expect(response).to be_success
    end

    it 'renders :new template' do
      expect(response).to render_template(:new)
    end
  end

  describe 'GET #edit' do
    before do
      Article.stub find: article
      get :edit, id: article
    end

    it 'finds article by id' do
      expect(Article).to have_received(:find).with(article.id.to_s)
    end

    it 'assigns @article' do
      expect(assigns(:article)).to eq(article)
    end

    it 'responds successfully' do
      expect(response).to be_success
    end

    it 'renders :edit template' do
      expect(response).to render_template(:edit)
    end
  end

  describe 'POST #create' do
    let(:new_article) { new_article = mock_model(Article) }

    context 'with valid attributes' do
      before do
        Article.stub new: new_article
        new_article.stub save: true
        post :create, article: attributes_for(:article)
      end

      it 'calls #save on the article' do
        expect(new_article).to have_received(:save)
      end

      it 'redirects to created article' do
        expect(response).to redirect_to(new_article)
      end
    end

    context 'with invalid attributes' do
      before do
        Article.stub new: new_article
        new_article.stub save: false
        post :create, article: attributes_for(:article)
      end

      it 'calls #save on the article' do
        expect(new_article).to have_received(:save)
      end

      it 'renders :new template' do
        expect(response).to render_template(:new)
      end

      it 'assigns new article to @article' do
        expect(assigns(:article)).to eq(new_article)
      end
    end
  end

  describe 'PATCH #update' do
    context 'with valid attributes' do
      let(:article_params) do
        { 'title' => 'Test title', 'content' => 'Lorem Ipsum' }
      end

      before do
        Article.stub find: article
        article.stub update: true
        patch :update, id: article, article: article_params
      end

      it 'finds the article by id' do
        expect(Article).to have_received(:find).with(article.id.to_s)
      end

      it 'calls #update on the article' do
        expect(article).to have_received(:update).with(article_params)
      end

      it 'redirects to the updated article' do
        expect(response).to redirect_to(article)
      end
    end

    context 'with invalid attributes' do
      let(:article_params) do
        { 'title' => 'Test title', 'content' => '' }
      end

      before do
        Article.stub find: article
        article.stub update: false
        patch :update, id: article, article: article_params
      end

      it 'finds the article by id' do
        expect(Article).to have_received(:find).with(article.id.to_s)
      end

      it 'calls #update on the article' do
        expect(article).to have_received(:update).with(article_params)
      end

      it 'renders :edit template' do
        expect(response).to render_template(:edit)
      end
    end
  end

  describe 'DELETE #destroy' do
    before do
      Article.stub find: article
      article.stub destroy: true
      delete :destroy, id: article
    end

    it 'finds the article by id' do
      expect(Article).to have_received(:find).with(article.id.to_s)
    end

    it 'calls #destroy on the article' do
      expect(article).to have_received(:destroy)
    end

    it 'redirects to articles' do
      expect(response).to redirect_to(articles_path)
    end
  end
end

Wanted a reference to a good succinct controller spec that mocks or stubs most actions to keep unit tests independent and upon which to build more complex controller specs as required.