creating an attribute in PostgresqlStorage class to save db_connection

string for restart function.

cnxauthoring/storage/postgresql.py

@@ -61,6 +61,7 @@ class PostgresqlStorage(BaseStorage):
     def __init__(self, db_connection_string=None):
         #initialize db
         self.conn = psycopg2.connect(db_connection_string)
+        self.db_connection_string = db_connection_string
 
     def get(self, type_=Document, **kwargs):
         """Retrieve ``Document`` objects from storage."""
@@ -369,4 +370,4 @@ def search(self, limits, type_=Document, submitter_id=None):
 
     def restart(self):
         """Restart the interface"""
-        self.conn = psycopg2.connect(self.conn.dsn)
+        self.conn = psycopg2.connect(self.db_connection_string)

cnxauthoring/tests/test_storage/test_postgresql.py

@@ -81,3 +81,22 @@ def test_add_get_and_remove_binder(self):
         self.assertEqual({k: tuple(sorted(v)) for k, v in result.acls.items()},
                          {'user2': ('view',)})
 
+    def test_restart(self):
+        from ...storage.database import CONNECTION_SETTINGS_KEY
+        import psycopg2
+        settings = integration_test_settings()
+        test_db = settings[CONNECTION_SETTINGS_KEY]
+        self.addCleanup(setattr, self.storage, 'conn', psycopg2.connect(test_db))
+
+        # 0 if the connection is open, nonzero if it is closed or broken.
+        OPEN = 0
+
+        self.assertEqual(self.storage.conn.closed, OPEN)
+
+        self.storage.conn.close()
+
+        self.assertNotEqual(self.storage.conn.closed, OPEN)
+
+        self.storage.restart()
+
+        self.assertEqual(self.storage.conn.closed, OPEN)