--- a/tests/test-diff-binary-file.t	Tue Sep 18 22:40:03 2018 -0400
+++ b/tests/test-diff-binary-file.t	Tue Sep 18 23:47:21 2018 -0400
@@ -83,7 +83,7 @@
   > path = sys.argv[1]
   > open(path, 'wb').write(b'\x00\x01\x02\x03')
   > EOF
-  $ $PYTHON writebin.py binfile.bin
+  $ "$PYTHON" writebin.py binfile.bin
   $ hg add binfile.bin
   $ hg ci -m 'add binfile.bin'