Correct support for adding empty text/byte strings
diff --git a/test/UsefulBuf_Tests.c b/test/UsefulBuf_Tests.c
index e729ff1..e93a011 100644
--- a/test/UsefulBuf_Tests.c
+++ b/test/UsefulBuf_Tests.c
@@ -57,6 +57,12 @@
    /* add a space to end */
    UsefulOutBuf_AppendByte(pUOB, ' ');
 
+   /* Add an empty string */
+   UsefulOutBuf_AppendUsefulBuf(pUOB, NULLUsefulBufC);
+
+   /* Add a zero length string (valid pointer, 0 length) */
+   UsefulOutBuf_AppendData(pUOB, "xxx", 0);
+
    /* Add 6 bytes to the end */
    UsefulBufC UBC = {"hunny ", 6};
    UsefulOutBuf_AppendUsefulBuf(pUOB, UBC);