add a test to verify truncated IDENTITY encoding when a blob has a

null byte in the middle

src/tests/id.vtc

@@ -52,6 +52,8 @@ varnish v1 -vcl {
 			      "the lazy dog" + req.url + req.http.unset + "",
 			      decoding=IDENTITY));
 
+	    set resp.http.truncated =
+              blobcode.encode(IDENTITY, blobcode.decode(HEX, "666f6f00626172"));
 	}
 } -start
 
@@ -66,4 +68,5 @@ client c1 {
 	expect resp.http.emptylist == ""
 	expect resp.http.param == "The quick brown fox jumps over the lazy dog"
 	expect resp.http.paramlist == "/The quick brown fox jumps over the lazy dog/"
+	expect resp.http.truncated == "foo"
 } -run