From d382e70d72f2213bcf296614dc429ba819da59e3 Mon Sep 17 00:00:00 2001
From: "Veronica K. B. Olsen" <1619840+vkbo@users.noreply.github.com>
Date: Wed, 30 Sep 2020 19:53:00 +0200
Subject: [PATCH] Fix a potential issue in the test suite

---
 tests/nwtools.py | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/tests/nwtools.py b/tests/nwtools.py
index 0b8896a3..e35d9e08 100644
--- a/tests/nwtools.py
+++ b/tests/nwtools.py
@@ -6,9 +6,12 @@ from itertools import chain
 
 from PyQt5.QtWidgets import qApp
 
-def cmpFiles(fileOne, fileTwo, ignoreLines=[]):
+def cmpFiles(fileOne, fileTwo, ignoreLines=None):
     """Compare two files, but optionally ignore lines given by a list.
     """
+    if ignoreLines is None:
+        ignoreLines = []
+
     try:
         foOne = open(fileOne, mode="r", encoding="utf8")
     except Exception as e: