From 3cf21e6edc14e8431a0a65867a45df35aef1911e Mon Sep 17 00:00:00 2001
From: Tamara Dahlgren <35777542+tldahlgren@users.noreply.github.com>
Date: Tue, 29 Oct 2019 00:25:59 -0700
Subject: [PATCH] bugfix: make `spack -d test test_changed_files` work 
 (#13229)

The `test_changed_files` in `test/cmd/flake8.py` was failing because it calls
`ArgumentParser.parse_args()` without arguments.  Normally that would just
parse `sys.argv` but it seems to fail because of something in either `spack test`
or `pytest`.  Call it with an empty array so that it doesn't try to touch`sys.argv`
at all.

- [x] allow `-d` spack option for `test_changed_files`
---
 lib/spack/spack/test/cmd/flake8.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/spack/spack/test/cmd/flake8.py b/lib/spack/spack/test/cmd/flake8.py
index b95db93364..6cad6950ba 100644
--- a/lib/spack/spack/test/cmd/flake8.py
+++ b/lib/spack/spack/test/cmd/flake8.py
@@ -45,7 +45,7 @@ def flake8_package():
 
 
 def test_changed_files(parser, flake8_package):
-    args = parser.parse_args()
+    args = parser.parse_args([])
 
     # changed_files returns file paths relative to the root
     # directory of Spack. Convert to absolute file paths.