Make test logs easier to read.

Tagging every message in tests makes the logs really wide. It's great
for grepping, but annoying to open in an editor or a narrow terminal.
Try out a different approach: spit out a heading before each test.

activesupport/lib/active_support/testing/tagged_logging.rb

@@ -1,26 +1,25 @@
 module ActiveSupport
   module Testing
-    module TaggedLogging
+    # Logs a "PostsControllerTest: test name" heading before each test to
+    # make test.log easier to search and follow along with.
+    module TaggedLogging #:nodoc:
       attr_writer :tagged_logger
 
       def before_setup
-        tagged_logger.push_tags(self.class.name, __name__) if tagged_logging?
-        super
-      end
-
-      def after_teardown
+        if tagged_logger
+          heading = "#{self.class}: #{__name__}"
+          divider = '-' * heading.size
+          tagged_logger.info divider
+          tagged_logger.info heading
+          tagged_logger.info divider
+        end
         super
-        tagged_logger.pop_tags(2) if tagged_logging?
       end
 
       private
         def tagged_logger
           @tagged_logger ||= (defined?(Rails.logger) && Rails.logger)
         end
-
-        def tagged_logging?
-          tagged_logger && tagged_logger.respond_to?(:push_tags)
-        end
     end
   end
 end

activesupport/test/test_test.rb

@@ -182,7 +182,6 @@ def before_setup
   end
 
   def test_logs_tagged_with_current_test_case
-    tagged_logger.info 'test'
-    assert_equal "[#{self.class.name}] [#{__name__}] test\n", @out.string
+    assert_match "#{self.class}: #{__name__}\n", @out.string
   end
 end