diff --git a/tests/constraints/tests.py b/tests/constraints/tests.py
index 4032b418b4..d4054dfd77 100644
--- a/tests/constraints/tests.py
+++ b/tests/constraints/tests.py
@@ -685,6 +685,20 @@ class UniqueConstraintTests(TestCase):
             exclude={"color"},
         )
 
+    def test_validate_expression_str(self):
+        constraint = models.UniqueConstraint("name", name="name_uniq")
+        msg = "Constraint “name_uniq” is violated."
+        with self.assertRaisesMessage(ValidationError, msg):
+            constraint.validate(
+                UniqueConstraintProduct,
+                UniqueConstraintProduct(name=self.p1.name),
+            )
+        constraint.validate(
+            UniqueConstraintProduct,
+            UniqueConstraintProduct(name=self.p1.name),
+            exclude={"name"},
+        )
+
     def test_name(self):
         constraints = get_constraints(UniqueConstraintProduct._meta.db_table)
         expected_name = "name_color_uniq"