add tests

spec/features/issuable_sidebar_spec.rb

+require 'spec_helper'
+
+feature 'Issuable sidebar', feature: true do
+  include SortingHelper
+
+  let(:project) { create(:project) }
+  let!(:user)   { create(:user)}
+  let(:merge_request) { create(:merge_request, :with_diffs, source_project: project) }
+
+  before do
+    project.team << [user, :master]
+
+    login_as user
+
+    visit namespace_project_merge_request_path(project.namespace, project, merge_request)
+  end
+
+  context 'changing tabs', js: true do
+
+    context 'between commits and changes for md' do
+
+      before do
+        page.driver.browser.resize(1024, 600)
+      end
+
+      it 'should show the right sidebar on commits tab' do
+        page.find('.commits-tab').click
+
+        expect(page).to have_selector('.right-sidebar-expanded')
+      end
+
+      it 'should collapse the right sidebar on changes tab' do
+        page.find('.diffs-tab').click
+
+        expect(page).to have_selector('.right-sidebar-collapsed')
+      end
+    end
+
+    context 'between discussion and changes for md' do
+
+      before do
+        page.driver.browser.resize(1024, 600)
+      end
+
+      it 'should show the right sidebar on discussion tab' do
+        page.find('.notes-tab').click
+
+        expect(page).to have_selector('.right-sidebar-expanded')
+      end
+
+      it 'should collapse the right sidebar on commits tab' do
+        page.find('.diffs-tab').click
+
+        expect(page).to have_selector('.right-sidebar-collapsed')
+      end
+    end
+
+    context 'when user collapse right sidebar for md' do
+
+      before do
+        page.driver.browser.resize(1024, 600)
+
+        page.find('.js-sidebar-toggle').click
+      end
+
+      it 'should not show the right sidebar on commits tab' do
+        page.find('.notes-tab').click
+
+        expect(page).to have_selector('.right-sidebar-collapsed')
+      end
+
+      it 'should not show the right sidebar on changes tab' do
+        page.find('.diffs-tab').click
+
+        expect(page).to have_selector('.right-sidebar-collapsed')
+      end
+    end
+
+    context 'between commits and changes for lg' do
+
+      before do
+        page.driver.browser.resize(1440, 600)
+      end
+
+      it 'should show the right sidebar on commits tab' do
+        page.find('.commits-tab').click
+
+        expect(page).to have_selector('.right-sidebar-expanded')
+      end
+
+      it 'should not collapse the right sidebar on changes tab' do
+        page.find('.diffs-tab').click
+
+        expect(page).to have_selector('.right-sidebar-expanded')
+      end
+    end
+
+    context 'between discussion and changes for lg' do
+
+      before do
+        page.driver.browser.resize(1440, 600)
+      end
+
+      it 'should show the right sidebar on discussion tab' do
+        page.find('.notes-tab').click
+
+        expect(page).to have_selector('.right-sidebar-expanded')
+      end
+
+      it 'should not collapse the right sidebar on commits tab' do
+        page.find('.diffs-tab').click
+
+        expect(page).to have_selector('.right-sidebar-expanded')
+      end
+    end
+  end
+end