Fix backward compability on GraphQLTestCase._client setter

graphene_django/utils/testing.py

@@ -101,6 +101,10 @@ def query(
         )
 
     @property
+    def _client(self):
+        pass
+
+    @_client.getter
     def _client(self):
         warnings.warn(
             "Using `_client` is deprecated in favour of `client`.",
@@ -109,6 +113,15 @@ def _client(self):
         )
         return self.client
 
+    @_client.setter
+    def _client(self, client):
+        warnings.warn(
+            "Using `_client` is deprecated in favour of `client`.",
+            PendingDeprecationWarning,
+            stacklevel=2,
+        )
+        self.client = client
+
     def assertResponseNoErrors(self, resp, msg=None):
         """
         Assert that the call went through correctly. 200 means the syntax is ok, if there are no `errors`,

graphene_django/utils/tests/test_testing.py

@@ -2,12 +2,13 @@
 
 from .. import GraphQLTestCase
 from ...tests.test_types import with_local_registry
+from django.test import Client
 
 
 @with_local_registry
-def test_graphql_test_case_deprecated_client():
+def test_graphql_test_case_deprecated_client_getter():
     """
-    Test that `GraphQLTestCase._client`'s should raise pending deprecation warning.
+    `GraphQLTestCase._client`' getter should raise pending deprecation warning.
     """
 
     class TestClass(GraphQLTestCase):
@@ -22,3 +23,23 @@ def runTest(self):
 
     with pytest.warns(PendingDeprecationWarning):
         tc._client
+
+
+@with_local_registry
+def test_graphql_test_case_deprecated_client_setter():
+    """
+    `GraphQLTestCase._client`' setter should raise pending deprecation warning.
+    """
+
+    class TestClass(GraphQLTestCase):
+        GRAPHQL_SCHEMA = True
+
+        def runTest(self):
+            pass
+
+    tc = TestClass()
+    tc._pre_setup()
+    tc.setUpClass()
+
+    with pytest.warns(PendingDeprecationWarning):
+        tc._client = Client()