Test filter by null values

tests/conftest.py

@@ -43,6 +43,7 @@
     user_2_comment_for_one_u1_post,
     user_2_posts,
     user_3,
+    user_4,
     workplace_1,
     workplace_2,
 )

tests/fixtures/entities.py

@@ -70,6 +70,19 @@ async def user_3(async_session: AsyncSession):
     await async_session.commit()
 
 
+@async_fixture()
+async def user_4(async_session: AsyncSession):
+    user = build_user(
+        email=None
+    )
+    async_session.add(user)
+    await async_session.commit()
+    await async_session.refresh(user)
+    yield user
+    await async_session.delete(user)
+    await async_session.commit()
+
+
 async def build_user_bio(async_session: AsyncSession, user: User, **fields):
     bio = UserBio(user=user, **fields)
     async_session.add(bio)

tests/test_api/test_api_sqla_with_includes.py

@@ -1751,6 +1751,34 @@ async def test_field_filters_with_values_from_different_models(
             "meta": {"count": 0, "totalPages": 1},
         }
 
+    @mark.parametrize("filter_dict, expected_email_is_null", [
+        param([{"name": "email", "op": "is_", "val": None}], True),
+        param([{"name": "email", "op": "isnot", "val": None}], False)
+    ])
+    async def test_filter_by_null(
+            self,
+            app: FastAPI,
+            client: AsyncClient,
+            user_1: User,
+            user_4: User,
+            filter_dict,
+            expected_email_is_null
+    ):
+        assert user_1.email is not None
+        assert user_4.email is None
+
+        url = app.url_path_for("get_user_list")
+        params = {"filter": dumps(filter_dict)}
+
+        response = await client.get(url, params=params)
+        assert response.status_code == 200, response.text
+
+        data = response.json()
+
+        assert len(data['data']) == 1
+        assert (data['data'][0]['attributes']['email'] is None) == expected_email_is_null
+
+
     async def test_composite_filter_by_one_field(
         self,
         app: FastAPI,