diff --git a/tests/test_submission.py b/tests/test_submission.py
index ed30b5a9..6bee2c01 100644
--- a/tests/test_submission.py
+++ b/tests/test_submission.py
@@ -75,9 +75,9 @@ def test_create_files(self):
         testdir = tmp_directory_name()
         testpath = "./testfile.txt"
 
-        # Create test file and set cleanup
-        f = open(testpath, "a")
-        f.close()
+        with open(testpath, "a", encoding="utf-8") as f:
+            f.close()
+
         self.addCleanup(os.remove, testpath)
 
         # Create submission and set values for testing