diff --git a/tests/test_util_pycompat.py b/tests/test_util_pycompat.py
index a815d1c4f..6ffc83f84 100644
--- a/tests/test_util_pycompat.py
+++ b/tests/test_util_pycompat.py
@@ -15,28 +15,26 @@ from sphinx.util import logging
 from sphinx.util.pycompat import execfile_
 
 
-def test_execfile_python2(capsys, app, status, warning):
+def test_execfile_python2(capsys, app, status, warning, tempdir):
     logging.setup(app, status, warning)
 
-    ns = {}
-    with tempfile.NamedTemporaryFile() as tmp:
-        tmp.write(b'print "hello"\n')
-        tmp.flush()
-        execfile_(tmp.name, ns)
+    conf_py = tempdir / 'conf.py'
+    conf_py.write_bytes(b'print "hello"\n')
+    execfile_(conf_py, {})
+
     msg = (
         'Support for evaluating Python 2 syntax is deprecated '
         'and will be removed in Sphinx 4.0. '
-        'Convert %s to Python 3 syntax.\n' % tmp.name)
+        'Convert %s to Python 3 syntax.\n' % conf_py)
     assert msg in strip_escseq(warning.getvalue())
     captured = capsys.readouterr()
     assert captured.out == 'hello\n'
 
 
-def test_execfile(capsys):
-    ns = {}
-    with tempfile.NamedTemporaryFile() as tmp:
-        tmp.write(b'print("hello")\n')
-        tmp.flush()
-        execfile_(tmp.name, ns)
+def test_execfile(capsys, tempdir):
+    conf_py = tempdir / 'conf.py'
+    conf_py.write_bytes(b'print("hello")\n')
+    execfile_(conf_py, {})
+
     captured = capsys.readouterr()
     assert captured.out == 'hello\n'