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diff --git a/tests/nested_foreign_keys/tests.py b/tests/nested_foreign_keys/tests.py
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+from __future__ import absolute_import
+from django.test import TestCase
+
+from .models import Person, Movie, Event, Screening, ScreeningNullFK, Package, PackageNullFK
+
+
+# These are tests for #16715. The basic scheme is always the same: 3 models with
+# 2 relations. The first relation may be null, while the second is non-nullable.
+# In some cases, Django would pick the wrong join type for the second relation,
+# resulting in missing objects in the queryset.
+#
+#   Model A
+#   | (Relation A/B : nullable)
+#   Model B
+#   | (Relation B/C : non-nullable)
+#   Model C
+#
+# Because of the possibility of NULL rows resulting from the LEFT OUTER JOIN
+# between Model A and Model B (i.e. instances of A without reference to B),
+# the second join must also be LEFT OUTER JOIN, so that we do not ignore
+# instances of A that do not reference B.
+#
+# Relation A/B can either be an explicit foreign key or an implicit reverse
+# relation such as introduced by one-to-one relations (through multi-table
+# inheritance).
+class NestedForeignKeysTests(TestCase):
+    def setUp(self):
+        self.director = Person.objects.create(name='Terry Gilliam / Terry Jones')
+        self.movie = Movie.objects.create(title='Monty Python and the Holy Grail', director=self.director)
+
+
+    # This test failed in #16715 because in some cases INNER JOIN was selected
+    # for the second foreign key relation instead of LEFT OUTER JOIN.
+    def testInheritance(self):
+        some_event = Event.objects.create()
+        screening = Screening.objects.create(movie=self.movie)
+
+        self.assertEqual(len(Event.objects.all()), 2)
+        self.assertEqual(len(Event.objects.select_related('screening')), 2)
+        # This failed.
+        self.assertEqual(len(Event.objects.select_related('screening__movie')), 2)
+
+        self.assertEqual(len(Event.objects.values()), 2)
+        self.assertEqual(len(Event.objects.values('screening__pk')), 2)
+        self.assertEqual(len(Event.objects.values('screening__movie__pk')), 2)
+        self.assertEqual(len(Event.objects.values('screening__movie__title')), 2)
+        # This failed.
+        self.assertEqual(len(Event.objects.values('screening__movie__pk', 'screening__movie__title')), 2)
+
+        # Simple filter/exclude queries for good measure.
+        self.assertEqual(Event.objects.filter(screening__movie=self.movie).count(), 1)
+        self.assertEqual(Event.objects.exclude(screening__movie=self.movie).count(), 1)
+
+
+    # These all work because the second foreign key in the chain has null=True.
+    def testInheritanceNullFK(self):
+        some_event = Event.objects.create()
+        screening = ScreeningNullFK.objects.create(movie=None)
+        screening_with_movie = ScreeningNullFK.objects.create(movie=self.movie)
+
+        self.assertEqual(len(Event.objects.all()), 3)
+        self.assertEqual(len(Event.objects.select_related('screeningnullfk')), 3)
+        self.assertEqual(len(Event.objects.select_related('screeningnullfk__movie')), 3)
+
+        self.assertEqual(len(Event.objects.values()), 3)
+        self.assertEqual(len(Event.objects.values('screeningnullfk__pk')), 3)
+        self.assertEqual(len(Event.objects.values('screeningnullfk__movie__pk')), 3)
+        self.assertEqual(len(Event.objects.values('screeningnullfk__movie__title')), 3)
+        self.assertEqual(len(Event.objects.values('screeningnullfk__movie__pk', 'screeningnullfk__movie__title')), 3)
+
+        self.assertEqual(Event.objects.filter(screeningnullfk__movie=self.movie).count(), 1)
+        self.assertEqual(Event.objects.exclude(screeningnullfk__movie=self.movie).count(), 2)
+
+    def test_null_exclude(self):
+        screening = ScreeningNullFK.objects.create(movie=None)
+        ScreeningNullFK.objects.create(movie=self.movie)
+        self.assertEqual(
+            list(ScreeningNullFK.objects.exclude(movie__id=self.movie.pk)),
+            [screening])
+
+    # This test failed in #16715 because in some cases INNER JOIN was selected
+    # for the second foreign key relation instead of LEFT OUTER JOIN.
+    def testExplicitForeignKey(self):
+        package = Package.objects.create()
+        screening = Screening.objects.create(movie=self.movie)
+        package_with_screening = Package.objects.create(screening=screening)
+
+        self.assertEqual(len(Package.objects.all()), 2)
+        self.assertEqual(len(Package.objects.select_related('screening')), 2)
+        self.assertEqual(len(Package.objects.select_related('screening__movie')), 2)
+
+        self.assertEqual(len(Package.objects.values()), 2)
+        self.assertEqual(len(Package.objects.values('screening__pk')), 2)
+        self.assertEqual(len(Package.objects.values('screening__movie__pk')), 2)
+        self.assertEqual(len(Package.objects.values('screening__movie__title')), 2)
+        # This failed.
+        self.assertEqual(len(Package.objects.values('screening__movie__pk', 'screening__movie__title')), 2)
+
+        self.assertEqual(Package.objects.filter(screening__movie=self.movie).count(), 1)
+        self.assertEqual(Package.objects.exclude(screening__movie=self.movie).count(), 1)
+
+
+    # These all work because the second foreign key in the chain has null=True.
+    def testExplicitForeignKeyNullFK(self):
+        package = PackageNullFK.objects.create()
+        screening = ScreeningNullFK.objects.create(movie=None)
+        screening_with_movie = ScreeningNullFK.objects.create(movie=self.movie)
+        package_with_screening = PackageNullFK.objects.create(screening=screening)
+        package_with_screening_with_movie = PackageNullFK.objects.create(screening=screening_with_movie)
+
+        self.assertEqual(len(PackageNullFK.objects.all()), 3)
+        self.assertEqual(len(PackageNullFK.objects.select_related('screening')), 3)
+        self.assertEqual(len(PackageNullFK.objects.select_related('screening__movie')), 3)
+
+        self.assertEqual(len(PackageNullFK.objects.values()), 3)
+        self.assertEqual(len(PackageNullFK.objects.values('screening__pk')), 3)
+        self.assertEqual(len(PackageNullFK.objects.values('screening__movie__pk')), 3)
+        self.assertEqual(len(PackageNullFK.objects.values('screening__movie__title')), 3)
+        self.assertEqual(len(PackageNullFK.objects.values('screening__movie__pk', 'screening__movie__title')), 3)
+
+        self.assertEqual(PackageNullFK.objects.filter(screening__movie=self.movie).count(), 1)
+        self.assertEqual(PackageNullFK.objects.exclude(screening__movie=self.movie).count(), 2)
+
+
+# Some additional tests for #16715. The only difference is the depth of the
+# nesting as we now use 4 models instead of 3 (and thus 3 relations). This
+# checks if promotion of join types works for deeper nesting too.
+class DeeplyNestedForeignKeysTests(TestCase):
+    def setUp(self):
+        self.director = Person.objects.create(name='Terry Gilliam / Terry Jones')
+        self.movie = Movie.objects.create(title='Monty Python and the Holy Grail', director=self.director)
+
+
+    def testInheritance(self):
+        some_event = Event.objects.create()
+        screening = Screening.objects.create(movie=self.movie)
+
+        self.assertEqual(len(Event.objects.all()), 2)
+        self.assertEqual(len(Event.objects.select_related('screening__movie__director')), 2)
+
+        self.assertEqual(len(Event.objects.values()), 2)
+        self.assertEqual(len(Event.objects.values('screening__movie__director__pk')), 2)
+        self.assertEqual(len(Event.objects.values('screening__movie__director__name')), 2)
+        self.assertEqual(len(Event.objects.values('screening__movie__director__pk', 'screening__movie__director__name')), 2)
+        self.assertEqual(len(Event.objects.values('screening__movie__pk', 'screening__movie__director__pk')), 2)
+        self.assertEqual(len(Event.objects.values('screening__movie__pk', 'screening__movie__director__name')), 2)
+        self.assertEqual(len(Event.objects.values('screening__movie__title', 'screening__movie__director__pk')), 2)
+        self.assertEqual(len(Event.objects.values('screening__movie__title', 'screening__movie__director__name')), 2)
+
+        self.assertEqual(Event.objects.filter(screening__movie__director=self.director).count(), 1)
+        self.assertEqual(Event.objects.exclude(screening__movie__director=self.director).count(), 1)
+
+
+    def testExplicitForeignKey(self):
+        package = Package.objects.create()
+        screening = Screening.objects.create(movie=self.movie)
+        package_with_screening = Package.objects.create(screening=screening)
+
+        self.assertEqual(len(Package.objects.all()), 2)
+        self.assertEqual(len(Package.objects.select_related('screening__movie__director')), 2)
+
+        self.assertEqual(len(Package.objects.values()), 2)
+        self.assertEqual(len(Package.objects.values('screening__movie__director__pk')), 2)
+        self.assertEqual(len(Package.objects.values('screening__movie__director__name')), 2)
+        self.assertEqual(len(Package.objects.values('screening__movie__director__pk', 'screening__movie__director__name')), 2)
+        self.assertEqual(len(Package.objects.values('screening__movie__pk', 'screening__movie__director__pk')), 2)
+        self.assertEqual(len(Package.objects.values('screening__movie__pk', 'screening__movie__director__name')), 2)
+        self.assertEqual(len(Package.objects.values('screening__movie__title', 'screening__movie__director__pk')), 2)
+        self.assertEqual(len(Package.objects.values('screening__movie__title', 'screening__movie__director__name')), 2)
+
+        self.assertEqual(Package.objects.filter(screening__movie__director=self.director).count(), 1)
+        self.assertEqual(Package.objects.exclude(screening__movie__director=self.director).count(), 1)