1. from django.test import TestCase

  2. 

  3. from .models import (

  4.     A,

  5.     B,

  6.     Building,

  7.     C,

  8.     Chick,

  9.     Child,

  10.     Class,

  11.     Client,

  12.     ClientStatus,

  13.     Connection,

  14.     Country,

  15.     Device,

  16.     Enrollment,

  17.     Hen,

  18.     Item,

  19.     Organizer,

  20.     Person,

  21.     Port,

  22.     SpecialClient,

  23.     State,

  24.     Student,

  25.     TUser,

  26. )

  27. 

  28. 

  29. class SelectRelatedRegressTests(TestCase):

  30.     def test_regression_7110(self):

  31.         """

  32.         Regression test for bug #7110.

  33. 

  34.         When using select_related(), we must query the

  35.         Device and Building tables using two different aliases (each) in order to

  36.         differentiate the start and end Connection fields. The net result is that

  37.         both the "connections = ..." queries here should give the same results

  38.         without pulling in more than the absolute minimum number of tables

  39.         (history has shown that it's easy to make a mistake in the implementation

  40.         and include some unnecessary bonus joins).

  41.         """

  42. 

  43.         b = Building.objects.create(name="101")

  44.         dev1 = Device.objects.create(name="router", building=b)

  45.         dev2 = Device.objects.create(name="switch", building=b)

  46.         dev3 = Device.objects.create(name="server", building=b)

  47.         port1 = Port.objects.create(port_number="4", device=dev1)

  48.         port2 = Port.objects.create(port_number="7", device=dev2)

  49.         port3 = Port.objects.create(port_number="1", device=dev3)

  50.         c1 = Connection.objects.create(start=port1, end=port2)

  51.         c2 = Connection.objects.create(start=port2, end=port3)

  52. 

  53.         connections = Connection.objects.filter(

  54.             start__device__building=b, end__device__building=b

  55.         ).order_by("id")

  56.         self.assertEqual(

  57.             [(c.id, str(c.start), str(c.end)) for c in connections],

  58.             [(c1.id, "router/4", "switch/7"), (c2.id, "switch/7", "server/1")],

  59.         )

  60. 

  61.         connections = (

  62.             Connection.objects.filter(

  63.                 start__device__building=b, end__device__building=b

  64.             )

  65.             .select_related()

  66.             .order_by("id")

  67.         )

  68.         self.assertEqual(

  69.             [(c.id, str(c.start), str(c.end)) for c in connections],

  70.             [(c1.id, "router/4", "switch/7"), (c2.id, "switch/7", "server/1")],

  71.         )

  72. 

  73.         # This final query should only have seven tables (port, device and building

  74.         # twice each, plus connection once). Thus, 6 joins plus the FROM table.

  75.         self.assertEqual(str(connections.query).count(" JOIN "), 6)

  76. 

  77.     def test_regression_8106(self):

  78.         """

  79.         Regression test for bug #8106.

  80. 

  81.         Same sort of problem as the previous test, but this time there are

  82.         more extra tables to pull in as part of the select_related() and some

  83.         of them could potentially clash (so need to be kept separate).

  84.         """

  85. 

  86.         us = TUser.objects.create(name="std")

  87.         usp = Person.objects.create(user=us)

  88.         uo = TUser.objects.create(name="org")

  89.         uop = Person.objects.create(user=uo)

  90.         s = Student.objects.create(person=usp)

  91.         o = Organizer.objects.create(person=uop)

  92.         c = Class.objects.create(org=o)

  93.         Enrollment.objects.create(std=s, cls=c)

  94. 

  95.         e_related = Enrollment.objects.select_related()[0]

  96.         self.assertEqual(e_related.std.person.user.name, "std")

  97.         self.assertEqual(e_related.cls.org.person.user.name, "org")

  98. 

  99.     def test_regression_8036(self):

  100.         """

  101.         Regression test for bug #8036

  102. 

  103.         the first related model in the tests below

  104.         ("state") is empty and we try to select the more remotely related

  105.         state__country. The regression here was not skipping the empty column results

  106.         for country before getting status.

  107.         """

  108. 

  109.         Country.objects.create(name="Australia")

  110.         active = ClientStatus.objects.create(name="active")

  111.         client = Client.objects.create(name="client", status=active)

  112. 

  113.         self.assertEqual(client.status, active)

  114.         self.assertEqual(Client.objects.select_related()[0].status, active)

  115.         self.assertEqual(Client.objects.select_related("state")[0].status, active)

  116.         self.assertEqual(

  117.             Client.objects.select_related("state", "status")[0].status, active

  118.         )

  119.         self.assertEqual(

  120.             Client.objects.select_related("state__country")[0].status, active

  121.         )

  122.         self.assertEqual(

  123.             Client.objects.select_related("state__country", "status")[0].status, active

  124.         )

  125.         self.assertEqual(Client.objects.select_related("status")[0].status, active)

  126. 

  127.     def test_multi_table_inheritance(self):

  128.         """Exercising select_related() with multi-table model inheritance."""

  129.         c1 = Child.objects.create(name="child1", value=42)

  130.         i1 = Item.objects.create(name="item1", child=c1)

  131.         i2 = Item.objects.create(name="item2")

  132. 

  133.         self.assertSequenceEqual(

  134.             Item.objects.select_related("child").order_by("name"),

  135.             [i1, i2],

  136.         )

  137. 

  138.     def test_regression_12851(self):

  139.         """

  140.         Regression for #12851

  141. 

  142.         Deferred fields are used correctly if you select_related a subset

  143.         of fields.

  144.         """

  145.         australia = Country.objects.create(name="Australia")

  146.         active = ClientStatus.objects.create(name="active")

  147. 

  148.         wa = State.objects.create(name="Western Australia", country=australia)

  149.         Client.objects.create(name="Brian Burke", state=wa, status=active)

  150.         burke = (

  151.             Client.objects.select_related("state")

  152.             .defer("state__name")

  153.             .get(name="Brian Burke")

  154.         )

  155. 

  156.         self.assertEqual(burke.name, "Brian Burke")

  157.         self.assertEqual(burke.state.name, "Western Australia")

  158. 

  159.         # Still works if we're dealing with an inherited class

  160.         SpecialClient.objects.create(

  161.             name="Troy Buswell", state=wa, status=active, value=42

  162.         )

  163.         troy = (

  164.             SpecialClient.objects.select_related("state")

  165.             .defer("state__name")

  166.             .get(name="Troy Buswell")

  167.         )

  168. 

  169.         self.assertEqual(troy.name, "Troy Buswell")

  170.         self.assertEqual(troy.value, 42)

  171.         self.assertEqual(troy.state.name, "Western Australia")

  172. 

  173.         # Still works if we defer an attribute on the inherited class

  174.         troy = (

  175.             SpecialClient.objects.select_related("state")

  176.             .defer("value", "state__name")

  177.             .get(name="Troy Buswell")

  178.         )

  179. 

  180.         self.assertEqual(troy.name, "Troy Buswell")

  181.         self.assertEqual(troy.value, 42)

  182.         self.assertEqual(troy.state.name, "Western Australia")

  183. 

  184.         # Also works if you use only, rather than defer

  185.         troy = (

  186.             SpecialClient.objects.select_related("state")

  187.             .only("name", "state")

  188.             .get(name="Troy Buswell")

  189.         )

  190. 

  191.         self.assertEqual(troy.name, "Troy Buswell")

  192.         self.assertEqual(troy.value, 42)

  193.         self.assertEqual(troy.state.name, "Western Australia")

  194. 

  195.     def test_null_join_promotion(self):

  196.         australia = Country.objects.create(name="Australia")

  197.         active = ClientStatus.objects.create(name="active")

  198. 

  199.         wa = State.objects.create(name="Western Australia", country=australia)

  200.         bob = Client.objects.create(name="Bob", status=active)

  201.         jack = Client.objects.create(name="Jack", status=active, state=wa)

  202.         qs = Client.objects.filter(state=wa).select_related("state")

  203.         with self.assertNumQueries(1):

  204.             self.assertEqual(list(qs), [jack])

  205.             self.assertEqual(qs[0].state, wa)

  206.             # The select_related join wasn't promoted as there was already an

  207.             # existing (even if trimmed) inner join to state.

  208.             self.assertNotIn("LEFT OUTER", str(qs.query))

  209.         qs = Client.objects.select_related("state").order_by("name")

  210.         with self.assertNumQueries(1):

  211.             self.assertEqual(list(qs), [bob, jack])

  212.             self.assertIs(qs[0].state, None)

  213.             self.assertEqual(qs[1].state, wa)

  214.             # The select_related join was promoted as there is already an

  215.             # existing join.

  216.             self.assertIn("LEFT OUTER", str(qs.query))

  217. 

  218.     def test_regression_19870(self):

  219.         hen = Hen.objects.create(name="Hen")

  220.         Chick.objects.create(name="Chick", mother=hen)

  221. 

  222.         self.assertEqual(Chick.objects.all()[0].mother.name, "Hen")

  223.         self.assertEqual(Chick.objects.select_related()[0].mother.name, "Hen")

  224. 

  225.     def test_regression_10733(self):

  226.         a = A.objects.create(name="a", lots_of_text="lots_of_text_a", a_field="a_field")

  227.         b = B.objects.create(name="b", lots_of_text="lots_of_text_b", b_field="b_field")

  228.         c = C.objects.create(

  229.             name="c", lots_of_text="lots_of_text_c", is_published=True, c_a=a, c_b=b

  230.         )

  231.         results = C.objects.only(

  232.             "name",

  233.             "lots_of_text",

  234.             "c_a",

  235.             "c_b",

  236.             "c_b__lots_of_text",

  237.             "c_a__name",

  238.             "c_b__name",

  239.         ).select_related()

  240.         self.assertSequenceEqual(results, [c])

  241.         with self.assertNumQueries(0):

  242.             qs_c = results[0]

  243.             self.assertEqual(qs_c.name, "c")

  244.             self.assertEqual(qs_c.lots_of_text, "lots_of_text_c")

  245.             self.assertEqual(qs_c.c_b.lots_of_text, "lots_of_text_b")

  246.             self.assertEqual(qs_c.c_a.name, "a")

  247.             self.assertEqual(qs_c.c_b.name, "b")

  248. 

  249.     def test_regression_22508(self):

  250.         building = Building.objects.create(name="101")

  251.         device = Device.objects.create(name="router", building=building)

  252.         Port.objects.create(port_number="1", device=device)

  253. 

  254.         device = Device.objects.get()

  255.         port = device.port_set.select_related("device__building").get()

  256.         with self.assertNumQueries(0):

  257.             port.device.building
About Sign Up Leave Feedback Contact