Account for Staging Ref in E2E context selector

Signed-off-by: Nailia Iskhakova <niskhakova@gitlab.com>

qa/qa/specs/helpers/context_selector.rb

@@ -45,11 +45,11 @@ module QA
 
               opts[:subdomain] = case option[:subdomain]
                                  when Array
-                                   "(#{option[:subdomain].join("|")})."
+                                   "(#{option[:subdomain].join("|")})\\."
                                  when Regexp
                                    option[:subdomain]
                                  else
-                                   "(#{option[:subdomain]})."
+                                   "(#{option[:subdomain]})\\."
                                  end
             end
           end

qa/spec/specs/helpers/context_selector_spec.rb

@@ -186,6 +186,24 @@ RSpec.describe QA::Specs::Helpers::ContextSelector do
     end
   end
 
+  context 'staging-ref' do
+    before do
+      QA::Runtime::Scenario.define(:gitlab_address, 'https://staging-ref.gitlab.com/')
+    end
+
+    it 'runs on staging-ref' do
+      group = describe_successfully do
+        it('does not run in staging', only: { subdomain: :staging }) {}
+        it('runs in staging-ref', only: { subdomain: /^staging-ref./ }) {}
+      end
+
+      aggregate_failures do
+        expect(group.examples[0].execution_result.status).to eq(:pending)
+        expect(group.examples[1].execution_result.status).to eq(:passed)
+      end
+    end
+  end
+
   context 'production' do
     before do
       QA::Runtime::Scenario.define(:gitlab_address, 'https://gitlab.com/')