1 files changed, 35 insertions, 0 deletions
diff --git a/tests/test_validators.py b/tests/test_validators.py
new file mode 100644
index 00000000..a1366a1a
--- /dev/null
+++ b/tests/test_validators.py
@@ -0,0 +1,35 @@
+from django.db import models
+from django.test import TestCase
+from rest_framework import serializers
+
+
+class ExampleModel(models.Model):
+    username = models.CharField(unique=True, max_length=100)
+
+
+class ExampleSerializer(serializers.ModelSerializer):
+    class Meta:
+        model = ExampleModel
+
+
+class TestUniquenessValidation(TestCase):
+    def setUp(self):
+        self.instance = ExampleModel.objects.create(username='existing')
+
+    def test_is_not_unique(self):
+        data = {'username': 'existing'}
+        serializer = ExampleSerializer(data=data)
+        assert not serializer.is_valid()
+        assert serializer.errors == {'username': ['This field must be unique.']}
+
+    def test_is_unique(self):
+        data = {'username': 'other'}
+        serializer = ExampleSerializer(data=data)
+        assert serializer.is_valid()
+        assert serializer.validated_data == {'username': 'other'}
+
+    def test_updated_instance_excluded(self):
+        data = {'username': 'existing'}
+        serializer = ExampleSerializer(self.instance, data=data)
+        assert serializer.is_valid()
+        assert serializer.validated_data == {'username': 'existing'}