diff --git a/tests/test__csv_reporter.py b/tests/test__csv_reporter.py
index bbe72cc..6ce7e42 100644
--- a/tests/test__csv_reporter.py
+++ b/tests/test__csv_reporter.py
@@ -39,8 +39,9 @@ def test_report_now(self):
             r.report_now()
 
         output_filename = os.path.join(self.path, "gauge1.csv")
-
-        output = open(output_filename).read()
+        
+        with open(output_filename) as f:
+            output = f.read()
         self.assertEqual(
             output.splitlines(), ["timestamp\tvalue", "1970-01-01 00:00:00\t123"]
         )