Added test for sigles support in extract

Change-Id: I5f5596a88da6314f0d1f7e8299fef7425f89a52f
diff --git a/MANIFEST b/MANIFEST
index 2496911..856b8f2 100755
--- a/MANIFEST
+++ b/MANIFEST
@@ -99,6 +99,7 @@
 t/sgbr/token.t
 t/script/single.t
 t/script/usage.t
+t/script/extract.t
 t/corpus/archive.zip
 t/corpus/BZK/header.xml
 t/corpus/GOE/header.xml