Wait for elasticsearch server before searching

Checks for a valid search response via the API using an
elasticsearch-only scope. Checks 3 times and raises an exception if
unable to search.

This gives the elasticsearch server time to be ready for the the
index to be created before the first test.

Waiting for a response takes time, so it should be enough to make 3
attempts with the default interval between attempts.

qa/qa.rb

@@ -36,6 +36,7 @@ module QA
     autoload :GPG, 'qa/runtime/gpg'
     autoload :MailHog, 'qa/runtime/mail_hog'
     autoload :IPAddress, 'qa/runtime/ip_address'
+    autoload :Search, 'qa/runtime/search'
 
     module API
       autoload :Client, 'qa/runtime/api/client'

qa/qa/runtime/search.rb

+# frozen_string_literal: true
+
+module QA
+  module Runtime
+    module Search
+      extend self
+      extend Support::Api
+
+      ElasticSearchServerError = Class.new(RuntimeError)
+
+      def elasticsearch_responding?
+        QA::Runtime::Logger.debug("Attempting to search via Elasticsearch...")
+
+        QA::Support::Retrier.retry_on_exception do
+          # We don't care about the results of the search, we just need
+          # any search that uses Elasticsearch, not the native search
+          # The Elasticsearch-only scopes are blobs, wiki_blobs, and commits.
+          request = Runtime::API::Request.new(api_client, "/search?scope=blobs&search=foo")
+          response = get(request.url)
+
+          unless response.code == singleton_class::HTTP_STATUS_OK
+            raise ElasticSearchServerError, "Search attempt failed. Request returned (#{response.code}): `#{response}`."
+          end
+
+          true
+        end
+      end
+
+      private
+
+      def api_client
+        @api_client ||= Runtime::API::Client.new(:gitlab)
+      end
+    end
+  end
+end

qa/qa/specs/features/ee/browser_ui/enablement/elasticsearch/advanced_global_advanced_syntax_search_spec.rb

@@ -17,6 +17,8 @@ module QA
           es.api_client = Runtime::API::Client.as_admin
         end
 
+        Runtime::Search.elasticsearch_responding?
+
         @project = Resource::Project.fabricate_via_api! do |project|
           project.add_name_uuid = false
           project.name = "es-adv-global-search-#{project_name_suffix}1"
@@ -50,6 +52,7 @@ module QA
         Page::Search::Results.perform do |results|
           results.switch_to_projects
 
+          expect(results).to have_content("Advanced search functionality is enabled")
           expect(results).to have_project(@project.name)
         end
       end

qa/qa/specs/features/ee/browser_ui/enablement/elasticsearch/elasticsearch_reindexing_spec.rb

@@ -14,6 +14,8 @@ module QA
           QA::EE::Resource::Settings::Elasticsearch.fabricate_via_browser_ui!
         end
 
+        Runtime::Search.elasticsearch_responding?
+
         @project = Resource::Project.fabricate_via_api! do |project|
           project.name = project_name
         end