Specs example

videos_controller_spec.rb

require 'rails_helper'

RSpec.describe VideosController, type: :controller do
  include Devise::Test::ControllerHelpers

  before { stub_video }

  describe '#show' do
    context 'user opens one of videos' do
      let(:user) { create :user }
      let(:video) { create :video }
      let!(:viewing_progress) { create :viewing_progress, user: user, video: video }

      before do
        sign_in user
      end

      it 'assigns @video' do
        get :show, params: { id: video.id }

        expect(assigns(:video)).to eq(video)
      end
  
      it 'assigns @progress' do
        get :show, params: { id: video.id }

        expect(assigns(:progress)).to eq viewing_progress
      end
    end
  end

  describe '#save_progress' do
    context 'logged in' do
      let(:user) { create :user }
      let(:video) { create :video }
      let(:viewing_progress) { user.viewing_progresses.where(video_id: video.id).take }
      let(:progress_params) { { time: 10, id: video.id } }
      before do
        create :viewing_progress, user: user # noise
        sign_in user
      end

      it 'creates ViewingProgress if there was none for given user and video' do
        post :save_progress, params: progress_params

        expect(viewing_progress).not_to be nil
      end

      context 'when new progress is behind persisted progress' do
        before { create :viewing_progress, user: user, video: video, time: 30 }

        it 'does not update ViewingProgress' do
          expect{ post :save_progress, params: progress_params }
            .to_not change{ viewing_progress.reload.time }
        end
      end

      context 'when new progress is ahead of persisted progress' do
        before { create :viewing_progress, user: user, video: video, time: 0 }

        it 'updates time progress for given video' do
          expect{ post :save_progress, params: progress_params }
            .to change{ viewing_progress.reload.time }
        end

        it 'updates percent progress for given video' do
          expect{ post :save_progress, params: progress_params }
            .to change{ viewing_progress.reload.percent }
        end

        describe 'updates is_viewed for given video' do
          it 'false when below 100%' do
            expect do
              post :save_progress,
                    params: { time: video.duration / 2, id: video.id }
            end.not_to change{ viewing_progress.reload.is_viewed }
          end

          it 'true when 90% or more' do
            expect do
              post :save_progress,
                    params: { time: video.duration * 0.9, id: video.id }
            end.to change{ viewing_progress.reload.is_viewed }
                     .from(false)
                     .to(true)
          end
        end
      end

      it 'returns json response' do
        post :save_progress, params: progress_params

        json_response = JSON.parse response.body
        expect(json_response).to eq({
          'success' => true,
          'video_id' => video.id,
          'time' => progress_params[:time]
        })
      end
    end

    context 'guest' do
      it 'does not create ant ViewingProgresses' do
        video = create :video
        user = create :user

        expect { post :save_progress, params: { time: 10, id: video.id } }
          .not_to change{ ViewingProgress.count }
      end
    end
  end
end