Add test to illustrate GH-295

tests/test_no_extra_queries.py

@@ -0,0 +1,16 @@
+from nose.tools import assert_false
+from mock import Mock, PropertyMock, patch
+from .models import Photo
+
+
+def test_dont_access_source():
+    """
+    Touching the source may trigger an unneeded query.
+    See <https://github.com/matthewwithanm/django-imagekit/issues/295>
+
+    """
+    pmock = PropertyMock()
+    pmock.__get__ = Mock()
+    with patch.object(Photo, 'original_image', pmock):
+        photo = Photo()  # noqa
+        assert_false(pmock.__get__.called)