diff --git a/src/common/buffer.cc b/src/common/buffer.cc
index 71a557536..743e19224 100644
--- a/src/common/buffer.cc
+++ b/src/common/buffer.cc
@@ -1123,6 +1123,7 @@ BufferTest::RunTests (void)
   i.WriteU8 (1, 100);
 
   buffer = Buffer (10);  
+  ENSURE_WRITTEN_BYTES (buffer, 10, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00);
   buffer.Begin ().WriteU8 (1);
   ENSURE_WRITTEN_BYTES (buffer, 10, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00);