diff --git a/src/testing/streams.c b/src/testing/streams.c
index d718ab76b..33c70c008 100644
--- a/src/testing/streams.c
+++ b/src/testing/streams.c
@@ -80,7 +80,7 @@ stream_xfr_alloc(nng_stream *s, void (*submit)(nng_stream *, nng_aio *),
 {
 	stream_xfr_t *x;
 
-	if ((x = nng_alloc(size)) == NULL) {
+	if ((x = nng_alloc(sizeof(*x))) == NULL) {
 		return (NULL);
 	}
 	if (nng_aio_alloc(&x->upper_aio, NULL, NULL) != 0) {