diff --git a/terraform/transform_config_test.go b/terraform/transform_config_test.go
index 81ce1fcab..31bb7c8e0 100644
--- a/terraform/transform_config_test.go
+++ b/terraform/transform_config_test.go
@@ -16,7 +16,7 @@ func TestConfigTransformer_nilModule(t *testing.T) {
 	}
 
 	if len(g.Vertices()) > 0 {
-		t.Fatalf("graph is not empty: %s", g)
+		t.Fatalf("graph is not empty: %s", g.String())
 	}
 }