Implement equality by ID on VirtualModel

Author: gasman

CHANGELOG.md

@@ -6,6 +6,7 @@ x.x (Unreleased)
 
 * Add `get_field` and `get_fields` methods to VirtualModel meta class (smark-1)
 * Add dedicated `DoesNotExist` and `MultipleObjectsReturned` exceptions on VirtualModel
+* Implement equality on VirtualModel based on ID
 * Make properties `start` and `stop` available in addition to `offset` and `limit`
 * Short-circuit queries if running on an empty slice
 * Fix: When retrieving by index, use a single-item slice instead of running the full query

queryish/__init__.py

@@ -306,3 +306,10 @@ def __str__(self):
 
     def __repr__(self):
         return f"<{self.__class__.__name__}: {str(self)}>"
+
+    def __eq__(self, other):
+        if type(self) is not type(other):
+            return False
+        if self.pk is None:
+            return other is self
+        return self.pk == other.pk

tests/test_rest.py

@@ -604,6 +604,34 @@ def test_instance_from_detail_lookup(self):
         self.assertEqual(result.name, "venusaur")
         self.assertEqual(result.id, 3)
 
+    @responses.activate
+    def test_equality(self):
+        responses.add(
+            responses.GET, "http://example.com/api/countries/",
+            match=[matchers.query_param_matcher({"id": 4})],
+            body="""
+                [
+                    {
+                        "id": 4,
+                        "name": "Japan",
+                        "continent": "asia"
+                    }
+                ]
+            """
+        )
+
+        country = Country.objects.get(id=4)
+        # match by ID and type
+        self.assertEqual(country, Country(id=4, name="Japan", continent="asia"))
+        self.assertEqual(country, Country(id=4, name="Nihon", continent="asia"))
+        self.assertNotEqual(country, Country(id=5, name="China", continent="asia"))
+        self.assertNotEqual(country, Pokemon(id=4, name="Charmander"))
+
+    def test_equality_on_unsaved_objects(self):
+        obj1 = Country(name="New Country", continent="oceania")
+        obj2 = Country(name="New Country", continent="oceania")
+        self.assertEqual(obj1, obj1)
+        self.assertNotEqual(obj1, obj2)
 
     @responses.activate
     def test_in_bulk(self):