Add EE specs for multiple clusters linking to list page

spec/ee/spec/features/show_project_spec.rb

+require 'spec_helper'
+
+describe 'Project show page', :feature do
+  describe 'stat button existence' do
+    let(:user) { create(:user) }
+
+    describe 'populated project' do
+      let(:project) { create(:project, :public, :repository) }
+
+      describe 'as a master' do
+        before do
+          project.add_master(user)
+          sign_in(user)
+
+          visit project_path(project)
+        end
+
+        it '"Kubernetes cluster" button linked to clusters page' do
+          create(:cluster, :provided_by_gcp, projects: [project])
+          create(:cluster, :provided_by_gcp, projects: [project])
+
+          visit project_path(project)
+
+          page.within('.project-stats') do
+            expect(page).to have_link('Kubernetes cluster', href: project_clusters_path(project))
+          end
+        end
+      end
+    end
+  end
+end