Address CR: factor out row deletion

tests/python/helpers.py

@@ -0,0 +1,11 @@
+"""Helpers for Python tests"""
+import common.helpers
+
+
+def delete_tables(engine, *table_names):
+    """Delete all rows from tables in `table_names' in order."""
+    with common.helpers.tables(engine, *table_names) as tables:
+        connection = tables[0]
+        tables = tables[1:]
+        for table in tables:
+            table.delete().execute()

tests/python/test_views.py

@@ -5,6 +5,7 @@
 
 from cycledash import app, db
 from common.helpers import tables, find
+from helpers import delete_tables
 import cycledash.views
 
 from test_projects_api import create_project_with_name
@@ -38,12 +39,7 @@ def setUp(self):
             self.run = dict(res.fetchone())
 
     def tearDown(self):
-        with tables(db.engine, 'projects', 'bams', 'vcfs', 'user_comments') \
-             as (con, projects, bams, runs, comments):
-            comments.delete().execute()
-            runs.delete().execute()
-            bams.delete().execute()
-            projects.delete().execute()
+        delete_tables(db.engine, 'user_comments', 'vcfs', 'bams', 'projects')
         self.ctx.pop()
         mocked.reset_mock()