diff --git a/t/test-dtmf-detect.c b/t/test-dtmf-detect.c
index bb142ba8f..20874f29f 100644
--- a/t/test-dtmf-detect.c
+++ b/t/test-dtmf-detect.c
@@ -646,6 +646,7 @@ int main(int argc, char **argv) {
 				"code 0 level -99 delay 816, "))
 		abort();
 
+	g_string_free(output, TRUE);
 	dtmf_rx_free(dtmf_dsp);
 
 	return 0;