Don't allow to modify answer's videos for started polls

Same rules that will apply for the answer itself should apply for the
attachments like videos, images, and/or documents.

spec/controllers/admin/poll/questions/answers/videos_controller_spec.rb

@@ -0,0 +1,87 @@
+require "rails_helper"
+
+describe Admin::Poll::Questions::Answers::VideosController, :admin do
+  let(:current_answer) { create(:poll_question_answer, poll: create(:poll)) }
+  let(:future_answer) { create(:poll_question_answer, poll: create(:poll, :future)) }
+
+  describe "POST create" do
+    it "is not possible for an already started poll" do
+      post :create, params: {
+        poll_question_answer_video: {
+         title: "Video from started poll",
+         url: "https://www.youtube.com/watch?v=-JMf43st-1A"
+       },
+       answer_id: current_answer
+      }
+
+      expect(flash[:alert]).to eq "You do not have permission to carry out the action 'create' on Video."
+      expect(Poll::Question::Answer::Video.count).to eq 0
+    end
+
+    it "is possible for a not started poll" do
+      post :create, params: {
+        poll_question_answer_video: {
+         title: "Video from not started poll",
+         url: "https://www.youtube.com/watch?v=-JMf43st-1A"
+        },
+        answer_id: future_answer
+      }
+
+      expect(response).to redirect_to admin_answer_videos_path(future_answer)
+      expect(flash[:notice]).to eq "Video created successfully"
+      expect(Poll::Question::Answer::Video.count).to eq 1
+    end
+  end
+
+  describe "PATCH update" do
+    it "is not possible for an already started poll" do
+      current_video = create(:poll_answer_video, answer: current_answer, title: "Sample title")
+
+      patch :update, params: {
+        poll_question_answer_video: {
+          title: "New title"
+        },
+        id: current_video,
+        answer_id: current_answer
+      }
+
+      expect(flash[:alert]).to eq "You do not have permission to carry out the action 'update' on Video."
+      expect(current_video.reload.title).to eq "Sample title"
+    end
+
+    it "is possible for a not started poll" do
+      future_video = create(:poll_answer_video, answer: future_answer)
+
+      patch :update, params: {
+        poll_question_answer_video: {
+          title: "New title"
+        },
+        id: future_video,
+        answer_id: future_answer
+      }
+
+      expect(response).to redirect_to admin_answer_videos_path(future_answer)
+      expect(flash[:notice]).to eq "Changes saved"
+      expect(future_video.reload.title).to eq "New title"
+    end
+  end
+
+  describe "DELETE destroy" do
+    it "is not possible for an already started poll" do
+      current_video = create(:poll_answer_video, answer: current_answer)
+      delete :destroy, params: { answer_id: current_answer, id: current_video }
+
+      expect(flash[:alert]).to eq "You do not have permission to carry out the action 'destroy' on Video."
+      expect(Poll::Question::Answer::Video.count).to eq 1
+    end
+
+    it "is possible for a not started poll" do
+      future_video = create(:poll_answer_video, answer: future_answer)
+      delete :destroy, params: { answer_id: future_answer, id: future_video }
+
+      expect(response).to redirect_to admin_answer_videos_path(future_answer)
+      expect(flash[:notice]).to eq "Answer video deleted successfully."
+      expect(Poll::Question::Answer::Video.count).to eq 0
+    end
+  end
+end