Add tests for nav sidebar collapsed on render

Adds rspec view tests that expect the nav sidebar
to have a class that will cause the nav sidebar
to be rendered collapsed with or without js.

Tests the nav sidebar on the admin, group,
instance statistics, user profile and project
sidebars.

spec/support/shared_examples/views/nav_sidebar.rb

+# frozen_string_literal: true
+
+shared_examples 'has nav sidebar' do
+  it 'has collapsed nav sidebar on mobile' do
+    render
+
+    expect(rendered).to have_selector('.nav-sidebar.sidebar-collapsed-mobile')
+  end
+end

spec/views/layouts/nav/sidebar/_admin.html.haml_spec.rb

@@ -26,6 +26,8 @@ describe 'layouts/nav/sidebar/_admin' do
     it_behaves_like 'page has active tab', 'Overview'
   end
 
+  it_behaves_like 'has nav sidebar'
+
   context 'on projects' do
     before do
       allow(controller).to receive(:controller_name).and_return('projects')

spec/views/layouts/nav/sidebar/_group.html.haml_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe 'layouts/nav/sidebar/_group' do
+  let(:group) { create(:group) }
+
+  before do
+    assign(:group, group)
+  end
+
+  it_behaves_like 'has nav sidebar'
+end

spec/views/layouts/nav/sidebar/_instance_statistics.html.haml_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe 'layouts/nav/sidebar/_instance_statistics' do
+  it_behaves_like 'has nav sidebar'
+end

spec/views/layouts/nav/sidebar/_profile.html.haml_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe 'layouts/nav/sidebar/_profile' do
+  let(:user) { create(:user) }
+
+  before do
+    allow(view).to receive(:current_user).and_return(user)
+  end
+
+  it_behaves_like 'has nav sidebar'
+end

spec/views/layouts/nav/sidebar/_project.html.haml_spec.rb

@@ -11,6 +11,8 @@ describe 'layouts/nav/sidebar/_project' do
     allow(view).to receive(:can?).and_return(true)
   end
 
+  it_behaves_like 'has nav sidebar'
+
   describe 'issue boards' do
     it 'has board tab' do
       render