--- a/tests/hghave.py	Tue Mar 03 15:56:00 2020 +0100
+++ b/tests/hghave.py	Fri Mar 06 23:04:58 2020 +0100
@@ -553,7 +553,7 @@
 @check("pyflakes", "Pyflakes python linter")
 def has_pyflakes():
     return matchoutput(
-        "sh -c \"echo 'import re' 2>&1 | pyflakes\"",
+        "sh -c \"echo 'import re' 2>&1 | $PYTHON -m pyflakes\"",
         br"<stdin>:1: 're' imported but unused",
         True,
     )