diff --git a/test/test_mbuf.c b/test/test_mbuf.c
index 598779a..be2df35 100644
--- a/test/test_mbuf.c
+++ b/test/test_mbuf.c
@@ -221,6 +221,7 @@ START_TEST (test_mbuf_static)
 
     uint8_t data[1024];
     struct MBuf mbuf;
+    uint8_t *p;
     
     uc_mbuf_init(&mbuf, data, 1000, 24, UC_MBUF_FL_STATIC);
 
@@ -234,6 +235,13 @@ START_TEST (test_mbuf_static)
     fail_if(mbuf.cookie != NULL);
     fail_if(mbuf.head != mbuf.tail);
     fail_if(mbuf.head != &data[24]);
+    p = uc_mbuf_put(&mbuf, 1000);
+    fail_if(p == NULL);
+    memset(p, 0xcc, 1000);
+    fail_if(uc_mbuf_len(&mbuf) != 1000);
+    p = uc_mbuf_put(&mbuf, 1);
+    fail_if(p != NULL);
+
 
     uc_mbuf_free(&mbuf);