Merged regressiontests and modeltests into the test root.

tests/distinct_on_fields/tests.py

@@ -0,0 +1,118 @@
+from __future__ import absolute_import
+
+from django.db.models import Max
+from django.test import TestCase, skipUnlessDBFeature
+from django.test.utils import str_prefix
+
+from .models import Tag, Celebrity, Fan, Staff, StaffTag
+
+class DistinctOnTests(TestCase):
+    def setUp(self):
+        t1 = Tag.objects.create(name='t1')
+        t2 = Tag.objects.create(name='t2', parent=t1)
+        t3 = Tag.objects.create(name='t3', parent=t1)
+        t4 = Tag.objects.create(name='t4', parent=t3)
+        t5 = Tag.objects.create(name='t5', parent=t3)
+
+        p1_o1 = Staff.objects.create(id=1, name="p1", organisation="o1")
+        p2_o1 = Staff.objects.create(id=2, name="p2", organisation="o1")
+        p3_o1 = Staff.objects.create(id=3, name="p3", organisation="o1")
+        p1_o2 = Staff.objects.create(id=4, name="p1", organisation="o2")
+        p1_o1.coworkers.add(p2_o1, p3_o1)
+        StaffTag.objects.create(staff=p1_o1, tag=t1)
+        StaffTag.objects.create(staff=p1_o1, tag=t1)
+
+        celeb1 = Celebrity.objects.create(name="c1")
+        celeb2 = Celebrity.objects.create(name="c2")
+
+        self.fan1 = Fan.objects.create(fan_of=celeb1)
+        self.fan2 = Fan.objects.create(fan_of=celeb1)
+        self.fan3 = Fan.objects.create(fan_of=celeb2)
+
+    @skipUnlessDBFeature('can_distinct_on_fields')
+    def test_basic_distinct_on(self):
+        """QuerySet.distinct('field', ...) works"""
+        # (qset, expected) tuples
+        qsets = (
+            (
+                Staff.objects.distinct().order_by('name'),
+                ['<Staff: p1>', '<Staff: p1>', '<Staff: p2>', '<Staff: p3>'],
+            ),
+            (
+                Staff.objects.distinct('name').order_by('name'),
+                ['<Staff: p1>', '<Staff: p2>', '<Staff: p3>'],
+            ),
+            (
+                Staff.objects.distinct('organisation').order_by('organisation', 'name'),
+                ['<Staff: p1>', '<Staff: p1>'],
+            ),
+            (
+                Staff.objects.distinct('name', 'organisation').order_by('name', 'organisation'),
+                ['<Staff: p1>', '<Staff: p1>', '<Staff: p2>', '<Staff: p3>'],
+            ),
+            (
+                Celebrity.objects.filter(fan__in=[self.fan1, self.fan2, self.fan3]).\
+                    distinct('name').order_by('name'),
+                ['<Celebrity: c1>', '<Celebrity: c2>'],
+            ),
+            # Does combining querysets work?
+            (
+                (Celebrity.objects.filter(fan__in=[self.fan1, self.fan2]).\
+                    distinct('name').order_by('name')
+                |Celebrity.objects.filter(fan__in=[self.fan3]).\
+                    distinct('name').order_by('name')),
+                ['<Celebrity: c1>', '<Celebrity: c2>'],
+            ),
+            (
+                StaffTag.objects.distinct('staff','tag'),
+                ['<StaffTag: t1 -> p1>'],
+            ),
+            (
+                Tag.objects.order_by('parent__pk', 'pk').distinct('parent'),
+                ['<Tag: t2>', '<Tag: t4>', '<Tag: t1>'],
+            ),
+            (
+                StaffTag.objects.select_related('staff').distinct('staff__name').order_by('staff__name'),
+                ['<StaffTag: t1 -> p1>'],
+            ),
+            # Fetch the alphabetically first coworker for each worker
+            (
+                (Staff.objects.distinct('id').order_by('id', 'coworkers__name').
+                               values_list('id', 'coworkers__name')),
+                [str_prefix("(1, %(_)s'p2')"), str_prefix("(2, %(_)s'p1')"),
+                 str_prefix("(3, %(_)s'p1')"), "(4, None)"]
+            ),
+        )
+        for qset, expected in qsets:
+            self.assertQuerysetEqual(qset, expected)
+            self.assertEqual(qset.count(), len(expected))
+
+        # Combining queries with different distinct_fields is not allowed.
+        base_qs = Celebrity.objects.all()
+        self.assertRaisesMessage(
+            AssertionError,
+            "Cannot combine queries with different distinct fields.",
+            lambda: (base_qs.distinct('id') & base_qs.distinct('name'))
+        )
+
+        # Test join unreffing
+        c1 = Celebrity.objects.distinct('greatest_fan__id', 'greatest_fan__fan_of')
+        self.assertIn('OUTER JOIN', str(c1.query))
+        c2 = c1.distinct('pk')
+        self.assertNotIn('OUTER JOIN', str(c2.query))
+
+    @skipUnlessDBFeature('can_distinct_on_fields')
+    def test_distinct_not_implemented_checks(self):
+        # distinct + annotate not allowed
+        with self.assertRaises(NotImplementedError):
+            Celebrity.objects.annotate(Max('id')).distinct('id')[0]
+        with self.assertRaises(NotImplementedError):
+            Celebrity.objects.distinct('id').annotate(Max('id'))[0]
+
+        # However this check is done only when the query executes, so you
+        # can use distinct() to remove the fields before execution.
+        Celebrity.objects.distinct('id').annotate(Max('id')).distinct()[0]
+        # distinct + aggregate not allowed
+        with self.assertRaises(NotImplementedError):
+            Celebrity.objects.distinct('id').aggregate(Max('id'))
+