1 """

     2 Make sure that the content type cache (see ContentTypeManager) works correctly.

     3 Lookups for a particular content type -- by model or by ID -- should hit the

     4 database only on the first lookup.

     5 

     6 First, let's make sure we're dealing with a blank slate (and that DEBUG is on so

     7 that queries get logged)::

     8 

     9     >>> from django.conf import settings

    10     >>> settings.DEBUG = True

    11 

    12     >>> from django.contrib.contenttypes.models import ContentType

    13     >>> ContentType.objects.clear_cache()

    14 

    15     >>> from django import db

    16     >>> db.reset_queries()

    17     

    18 At this point, a lookup for a ContentType should hit the DB::

    19 

    20     >>> ContentType.objects.get_for_model(ContentType)

    21     <ContentType: content type>

    22     

    23     >>> len(db.connection.queries)

    24     1

    25 

    26 A second hit, though, won't hit the DB, nor will a lookup by ID::

    27 

    28     >>> ct = ContentType.objects.get_for_model(ContentType)

    29     >>> len(db.connection.queries)

    30     1

    31     >>> ContentType.objects.get_for_id(ct.id)

    32     <ContentType: content type>

    33     >>> len(db.connection.queries)

    34     1

    35 

    36 Once we clear the cache, another lookup will again hit the DB::

    37 

    38     >>> ContentType.objects.clear_cache()

    39     >>> ContentType.objects.get_for_model(ContentType)

    40     <ContentType: content type>

    41     >>> len(db.connection.queries)

    42     2

    43 

    44 Don't forget to reset DEBUG!

    45 

    46     >>> settings.DEBUG = False

    47 """