Further client config work
diff --git a/test/core/end2end/fixtures/chttp2_fullstack.c b/test/core/end2end/fixtures/chttp2_fullstack.c
index e647434..8a1530e 100644
--- a/test/core/end2end/fixtures/chttp2_fullstack.c
+++ b/test/core/end2end/fixtures/chttp2_fullstack.c
@@ -73,6 +73,7 @@
                                   grpc_channel_args *client_args) {
   fullstack_fixture_data *ffd = f->fixture_data;
   f->client = grpc_channel_create(ffd->localaddr, client_args);
+  GPR_ASSERT(f->client);
 }
 
 void chttp2_init_server_fullstack(grpc_end2end_test_fixture *f,