Ensure no notification is on the queue before running notifications related tests.

actionpack/test/activerecord/controller_runtime_test.rb

@@ -23,6 +23,8 @@ def wait
   end
 
   def test_log_with_active_record
+    # Wait pending notifications to be published
+    wait
     get :show
     wait
     assert_match /ActiveRecord runtime/, @controller.logger.logged[3]

actionpack/test/controller/caching_test.rb

@@ -630,6 +630,8 @@ def test_fragment_for
   end
 
   def test_fragment_for_logging
+    # Wait pending notifications to be published
+    ActiveSupport::Notifications.notifier.wait
     @controller.logger = MockLogger.new
 
     fragment_computed = false

actionpack/test/controller/logging_test.rb

@@ -19,6 +19,7 @@ class LoggingTest < ActionController::TestCase
 
   def setup
     super
+    wait # Wait pending notifications to be published
     set_logger
   end
 

actionpack/test/dispatch/show_exceptions_test.rb

@@ -106,6 +106,9 @@ class ShowExceptionsTest < ActionController::IntegrationTest
   end
 
   test "publishes notifications" do
+    # Wait pending notifications to be published
+    ActiveSupport::Notifications.notifier.wait
+
     @app, event = ProductionApp, nil
     self.remote_addr = '127.0.0.1'