Issue python#27952: Capture stderr in run_script()

Author: berkerpeksag

Lib/test/test_tools/test_fixcid.py

@@ -83,7 +83,8 @@ def run_script(self, input="", *, args=("-",), substfile="xx yy\n"):
         script = os.path.join(scriptsdir, "fixcid.py")
         with support.swap_attr(sys, "argv", argv), \
                 support.swap_attr(sys, "stdin", StringIO(input)), \
-                support.captured_stdout() as output:
+                support.captured_stdout() as output, \
+                support.captured_stderr():
             try:
                 runpy.run_path(script, run_name="__main__")
             except SystemExit as exit: