1 files changed, 44 insertions, 0 deletions
diff --git a/tests/invalid_models_tests/test_models.py b/tests/invalid_models_tests/test_models.py
index f3f0bc8bd5..6bfdf2e736 100644
--- a/tests/invalid_models_tests/test_models.py
+++ b/tests/invalid_models_tests/test_models.py
@@ -1414,3 +1414,47 @@ class ConstraintsTests(TestCase):
                 ]
 
         self.assertEqual(Model.check(databases=self.databases), [])
+
+    def test_deferrable_unique_constraint(self):
+        class Model(models.Model):
+            age = models.IntegerField()
+
+            class Meta:
+                constraints = [
+                    models.UniqueConstraint(
+                        fields=['age'],
+                        name='unique_age_deferrable',
+                        deferrable=models.Deferrable.DEFERRED,
+                    ),
+                ]
+
+        errors = Model.check(databases=self.databases)
+        expected = [] if connection.features.supports_deferrable_unique_constraints else [
+            Warning(
+                '%s does not support deferrable unique constraints.'
+                % connection.display_name,
+                hint=(
+                    "A constraint won't be created. Silence this warning if "
+                    "you don't care about it."
+                ),
+                obj=Model,
+                id='models.W038',
+            ),
+        ]
+        self.assertEqual(errors, expected)
+
+    def test_deferrable_unique_constraint_required_db_features(self):
+        class Model(models.Model):
+            age = models.IntegerField()
+
+            class Meta:
+                required_db_features = {'supports_deferrable_unique_constraints'}
+                constraints = [
+                    models.UniqueConstraint(
+                        fields=['age'],
+                        name='unique_age_deferrable',
+                        deferrable=models.Deferrable.IMMEDIATE,
+                    ),
+                ]
+
+        self.assertEqual(Model.check(databases=self.databases), [])