diff --git a/tests/unit/test_client.py b/tests/unit/test_client.py
index 614bf4bde6..09cf61f9ab 100644
--- a/tests/unit/test_client.py
+++ b/tests/unit/test_client.py
@@ -150,6 +150,8 @@ def test_constructor_custom_client_info(self):
         self._constructor_test_helper(expected_scopes, creds, client_info=client_info)
 
     def test_constructor_implicit_credentials(self):
+        from google.cloud.spanner_v1 import client as MUT
+
         creds = _make_credentials()
 
         patch = mock.patch("google.auth.default", return_value=(creds, None))
@@ -158,7 +160,7 @@ def test_constructor_implicit_credentials(self):
                 None, None, expected_creds=creds.with_scopes.return_value
             )
 
-        default.assert_called_once_with()
+        default.assert_called_once_with(scopes=(MUT.SPANNER_ADMIN_SCOPE,))
 
     def test_constructor_credentials_wo_create_scoped(self):
         creds = _make_credentials()