diff --git a/activerecord/test/cases/tasks/mysql_rake_test.rb b/activerecord/test/cases/tasks/mysql_rake_test.rb
index 572ad2ed18..3e3a2828f3 100644
--- a/activerecord/test/cases/tasks/mysql_rake_test.rb
+++ b/activerecord/test/cases/tasks/mysql_rake_test.rb
@@ -288,25 +288,6 @@ module ActiveRecord
         @configuration.merge('port' => 10000),
         filename)
     end
-
-    private
-
-    def capture(stream)
-      stream = stream.to_s
-      captured_stream = Tempfile.new(stream)
-      stream_io = eval("$#{stream}")
-      origin_stream = stream_io.dup
-      stream_io.reopen(captured_stream)
-
-      yield
-
-      stream_io.rewind
-      return captured_stream.read
-    ensure
-      captured_stream.close
-      captured_stream.unlink
-      stream_io.reopen(origin_stream)
-    end
   end
 
   class MySQLStructureLoadTest < ActiveRecord::TestCase
diff --git a/activerecord/test/cases/test_case.rb b/activerecord/test/cases/test_case.rb
index b6c5511849..80aaead6d9 100644
--- a/activerecord/test/cases/test_case.rb
+++ b/activerecord/test/cases/test_case.rb
@@ -1,10 +1,33 @@
 require 'active_support/test_case'
 
 module ActiveRecord
+  # The +capture+ helper was deprecated because it is not thread safe.
+  # Our own tests still depend on it.
+  module UndeprecateCapture
+    def capture(stream)
+      stream = stream.to_s
+      captured_stream = Tempfile.new(stream)
+      stream_io = eval("$#{stream}")
+      origin_stream = stream_io.dup
+      stream_io.reopen(captured_stream)
+
+      yield
+
+      stream_io.rewind
+      return captured_stream.read
+    ensure
+      captured_stream.close
+      captured_stream.unlink
+      stream_io.reopen(origin_stream)
+    end
+  end
+
   # = Active Record Test Case
   #
   # Defines some test assertions to test against SQL queries.
   class TestCase < ActiveSupport::TestCase #:nodoc:
+    include UndeprecateCapture
+
     def teardown
       SQLCounter.clear_log
     end