--- a/tests/test-grep.t	Tue Sep 18 22:40:03 2018 -0400
+++ b/tests/test-grep.t	Tue Sep 18 23:47:21 2018 -0400
@@ -300,7 +300,7 @@
 
 match in last "line" without newline
 
-  $ $PYTHON -c 'fp = open("noeol", "wb"); fp.write(b"no infinite loop"); fp.close();'
+  $ "$PYTHON" -c 'fp = open("noeol", "wb"); fp.write(b"no infinite loop"); fp.close();'
   $ hg ci -Amnoeol
   adding noeol
   $ hg grep -r tip:0 loop