added support for SET XER decoder

diff --git a/tests/70-xer-test-OK.asn1 b/tests/70-xer-test-OK.asn1
index 19c8b6f..88deb43 100644
--- a/tests/70-xer-test-OK.asn1
+++ b/tests/70-xer-test-OK.asn1
@@ -16,7 +16,8 @@
 	 */
 
 	PDU ::= CHOICE {
-		sequence Sequence
+		sequence	Sequence,
+		set		Set
 	}
 
 	Sequence ::= SEQUENCE {
@@ -26,4 +27,9 @@
 		string		UTF8String
 	}
 
+	Set ::= SET {
+		roid		RELATIVE-OID,
+		opaque		OCTET STRING	OPTIONAL
+	}
+
 END