diff --git a/tests/test_writer_acceptance.py b/tests/test_writer_acceptance.py
index b260966..4a9b593 100644
--- a/tests/test_writer_acceptance.py
+++ b/tests/test_writer_acceptance.py
@@ -66,7 +66,7 @@ def tearDown(self):
         shutil.rmtree(DATASTORE_PATH / '2017')
 
     def test_event_acceptance(self):
-        self.writer_app.process_data(self.pickle_filename['CIC'])
+        self.writer_app.process_data(self.pickle_filename['CIC'], DATASTORE_PATH)
 
         data = self.read_table('events')
         self.assertEqual(data['timestamp'], 1488093964)
@@ -86,7 +86,7 @@ def test_event_acceptance(self):
         self.assertEqual(tr1, base64.decodebytes(tr1_b64))
 
     def test_singles_acceptance(self):
-        self.writer_app.process_data(self.pickle_filename['SIN'])
+        self.writer_app.process_data(self.pickle_filename['SIN'], DATASTORE_PATH)
 
         data = self.read_table('singles')
         self.assertEqual(data['timestamp'], 1488094031)
@@ -99,7 +99,7 @@ def test_singles_acceptance(self):
         self.assertEqual(len(blobs), 0)
 
     def test_weather_acceptance(self):
-        self.writer_app.process_data(self.pickle_filename['WTR'])
+        self.writer_app.process_data(self.pickle_filename['WTR'], DATASTORE_PATH)
 
         data = self.read_table('weather')
         self.assertEqual(data['timestamp'], 1488094084)
@@ -111,7 +111,7 @@ def test_weather_acceptance(self):
         self.assertEqual(len(blobs), 0)
 
     def test_config_acceptance(self):
-        self.writer_app.process_data(self.pickle_filename['CFG'])
+        self.writer_app.process_data(self.pickle_filename['CFG'], DATASTORE_PATH)
         data = self.read_table('config')
         self.assertEqual(data['timestamp'], 1488125225)
         self.assertEqual(data['mas_ch1_thres_high'], 320)
diff --git a/writer/storage.py b/writer/storage.py
index 61f2002..7e2061d 100644
--- a/writer/storage.py
+++ b/writer/storage.py
@@ -278,7 +278,7 @@ def open_or_create_file(data_dir, date):
     file = directory / f'{date.year}_{date.month}_{date.day}.h5'
 
     # Ensure dir and parent directories exist with mode rwxr-xr-x
-    directory.mkdir(mode=0o755, parents=True, exists_ok=True)
+    directory.mkdir(mode=0o755, parents=True, exist_ok=True)
 
     return tables.open_file(file, 'a')