diff --git a/tests/test_outputs.py b/tests/test_outputs.py
index 0f7c5a6..e1afb5c 100644
--- a/tests/test_outputs.py
+++ b/tests/test_outputs.py
@@ -16,8 +16,9 @@
 
 @pytest.fixture
 def csv_reader():
-    """Open test file and return csv.DictReader."""
-    return csv.DictReader(open(os.path.join(HERE, "drugbank_vocabulary_CC0_first_20_sample.csv"), 'r'))
+    """Open test file and prepare csv.DictReader."""
+    with open(os.path.join(HERE, "drugbank_vocabulary_CC0_first_20_sample.csv"), 'r') as csvfile:
+        yield csv.DictReader(csvfile)
 
 
 #