Improve order by type handling

CHANGES.rst

@@ -8,6 +8,8 @@ Here you can see the full list of changes between each SQLAlchemy-Utils release.
 ^^^^^^^^^^^^^^^^^^^
 
 - Fixed MapperEntity handling in get_mapper and get_tables utility functions
+- Fixed make_order_by_deterministic handling for queries without order by (no just silently ignores those rather than throws exception)
+- Made make_order_by_deterministic if given query uses strings as order by args
 
 
 0.27.1 (2014-10-20)

sqlalchemy_utils/functions/sort_query.py

@@ -1,3 +1,4 @@
+import six
 import sqlalchemy as sa
 from sqlalchemy.sql.expression import desc, asc
 
@@ -169,6 +170,9 @@ def make_order_by_deterministic(query):
 
     .. versionadded: 0.27.1
     """
+    if not query._order_by:
+        return query
+
     order_by = query._order_by[0]
     if isinstance(order_by, sa.Column):
         order_by_func = sa.asc
@@ -179,6 +183,10 @@ def make_order_by_deterministic(query):
         else:
             order_by_func = sa.asc
         column = order_by.get_children()[0]
+    elif isinstance(order_by, six.string_types):
+        raise TypeError(
+            'Order by str is not supported. Use SA Column objects instead.'
+        )
     else:
         raise TypeError('Only simple columns in query order by are supported.')
 

tests/functions/test_make_order_by_deterministic.py

@@ -49,3 +49,13 @@ class TestMakeOrderByDeterministic(TestCase):
         )
         query = make_order_by_deterministic(query)
         assert_contains('ORDER BY "user".name ASC, "user".id ASC', query)
+
+    def test_string_order_by(self):
+        query = self.session.query(self.User).order_by('name')
+        with raises(TypeError):
+            query = make_order_by_deterministic(query)
+
+    def test_query_without_order_by(self):
+        query = self.session.query(self.User)
+        query = make_order_by_deterministic(query)
+        assert 'ORDER BY' not in str(query)