diff --git a/test/test_helper.rb b/test/test_helper.rb
index d606d0589..6a48b6780 100644
--- a/test/test_helper.rb
+++ b/test/test_helper.rb
@@ -38,8 +38,14 @@ def Minitest.after_run(&block)
   end
 end
 
-require 'capture_warnings'
-CaptureWarnings.new(_fail_build = true).execute!
+# If there's no failure info, try disabling capturing stderr:
+# `env CAPTURE_STDERR=false rake`
+# This is way easier than writing a Minitest plugin
+# for 4.x and 5.x.
+if ENV['CAPTURE_STDERR'] !~ /false|1/i
+  require 'capture_warnings'
+  CaptureWarnings.new(_fail_build = true).execute!
+end
 
 require 'active_model_serializers'