Ensure in-memory application settings are cleared before each test

Signed-off-by: Rémy Coutable <remy@rymai.me>

lib/gitlab/current_settings.rb

@@ -13,6 +13,10 @@ module Gitlab
         Gitlab::FakeApplicationSettings.new(::ApplicationSetting.defaults.merge(attributes || {}))
       end
 
+      def clear_in_memory_application_settings!
+        instance_variable_set(:@in_memory_application_settings, nil)
+      end
+
       def method_missing(name, *args, &block)
         current_application_settings.send(name, *args, &block) # rubocop:disable GitlabSecurity/PublicSend
       end

spec/spec_helper.rb

@@ -135,6 +135,10 @@ RSpec.configure do |config|
     Fog.unmock! if Fog.mock?
   end
 
+  config.after(:example) do
+    Gitlab::CurrentSettings.clear_in_memory_application_settings!
+  end
+
   config.before(:example, :mailer) do
     reset_delivered_emails!
   end