Schema tests and .extra queryset method

[Maximiliano Robaina]

Running schema tests I caught an issue, more precisely, in test_add_field_default_transform.
At the end, this test method is doing:

self.assertEqual(Author.objects.extra(where=["thing = 1"]).count(), 2)

The problem here is what in this where clause, the "thing" field must be quoted.

In firebird :

    SELECT * FROM AUTHOR WHERE thing = 1   -- Here thing (in lowercase) and THING (in uppercase) are equivalent, are the same object

is different of:

    SELECT * FROM AUTHOR WHERE "thing" = 1   --  field is quoted

For a more generic test I think we need to avoid use .extra method or another raw sql statement.

For a more complete discussion about it, see at
​https://groups.google.com/forum/?hl=es#!topic/django-developers/KRHD77KlZ28

[Shai Berger]

Added some formatting to description.

We should be able to get rid of the raw sql there, since the model has the added column.