diff --git a/http2/transport_test.go b/http2/transport_test.go
index 8e91678..80f754b 100644
--- a/http2/transport_test.go
+++ b/http2/transport_test.go
@@ -203,7 +203,7 @@
 		}
 		return nil
 	}); err != nil {
-		t.Error("State of pool after CloseIdleConnections: %v", err)
+		t.Errorf("State of pool after CloseIdleConnections: %v", err)
 	}
 }