diff --git a/gprs_gb/Test.ttcn b/gprs_gb/Test.ttcn
new file mode 100644
index 0000000..88a78a8
--- /dev/null
+++ b/gprs_gb/Test.ttcn
@@ -0,0 +1,79 @@
+module Test {
+
+	import from BSSGP_Helper_Functions all;
+	import from BSSGP_Types all;
+
+	type component dummy_CT {
+	}
+
+	function f_assert_prepr(in octetstring a, in octetstring b) {
+		log ("Input: ", a);
+		log ("Expected: ", b);
+		var octetstring a_preprocessed := f_BSSGP_preprocess_pdu(a);
+		log ("Preprocessed: ", a_preprocessed);
+
+		if (a_preprocessed != b) {
+			setverdict(fail);
+		} else {
+			setverdict(pass);
+		}
+	}
+
+	function f_dec_and_log(in octetstring inp) {
+		log("Input: ", inp);
+		var octetstring inp_p := f_BSSGP_preprocess_pdu(inp);
+		log ("Preprocessed: ", inp_p);
+		var BssgpPdu dec := dec_BssgpPdu(inp_p);
+		log("Decoded: ", dec);
+	}
+
+	testcase TC_selftest() runs on dummy_CT {
+		const octetstring c_bvc_reset_pcu := '2204820000078108088832f44000c80051e0'O;
+		const octetstring c_bvc_reset_q := '2204820000078100'O;
+		const octetstring c_status_pcu := '4107810515882204820000078103'O;
+		const octetstring c_reset_ack_q := '2304820000'O;
+		const octetstring c_reset_ack_pcu := '23048200c4'O;
+		const octetstring c_unblock_pcu := '24048200c4'O;
+		const octetstring c_unblock_ack_q := '25048200c4'O;
+		const octetstring c_fc_bvc_pcu := '261e8101058200fa038200c8018200fa1c8200c806820000'O;
+		const octetstring c_fc_bvc_ack_q := '271e8101'O;
+		const octetstring c_gmm_mo_att_req := '01bb146ddd000004088832f44000c80051e000800e003b01c001080103e5e000110a0005f4fb146ddd32f44000c8001d1b53432b37159ef9090070000dd9c6321200e00019b32c642401c0002017057bf0ec'O;
+		const octetstring c_gmm_mt_ac_req := '00bb146ddd0050001682ffff0a8204030e9c41c001081200102198c72477ea104895e8b959acc58b108182f4d045'O;
+		const octetstring c_gmm_mo_ac_resp := '01bb146ddd000004088832f44000c80051e000800e000e01c00508130122fa361f5fdd623d'O;
+		const octetstring c_gmm_mt_att_acc := '00bb146ddd0050001682ffff0a8204030e9841c005080201340432f44000c8001805f4fb146ddd0967d0'O;
+		const octetstring c_gmm_mt_det_req := '00bb146ddd0050001682ffff0a8204030e8941c00908050215f0b6'O;
+		const octetstring c_gmm_mo_att_cpl := '01fb146ddd000004088832f44000c80051e000800e000801c009080339d7bc'O;
+
+		/* single byte length to two byte length */
+		f_assert_prepr('04058101'O, '0405000101'O);
+		f_assert_prepr('040589000102030405060708'O, '04050009000102030405060708'O);
+		/* two byte length to two byte length */
+		f_assert_prepr('0405000101'O, '0405000101'O);
+		/* special case: DL-UD + UL-UD */
+		f_assert_prepr('00aabbccddeeffaa29822342'O, '00aabbccddeeffaa2900022342'O);
+		f_assert_prepr('01aabbccddeeffaa29822342'O, '01aabbccddeeffaa2900022342'O);
+		/* multiple TLVs */
+		f_assert_prepr('234281aa4382bbbb'O, '23420001aa430002bbbb'O);
+		f_assert_prepr('230080'O, '23000000'O);
+
+		f_dec_and_log(c_bvc_reset_pcu);
+		f_dec_and_log(c_bvc_reset_q);
+		f_dec_and_log(c_status_pcu);
+		f_dec_and_log(c_reset_ack_q);
+		f_dec_and_log(c_reset_ack_pcu);
+		f_dec_and_log(c_unblock_pcu);
+		f_dec_and_log(c_unblock_ack_q);
+		f_dec_and_log(c_fc_bvc_pcu);
+		f_dec_and_log(c_fc_bvc_ack_q);
+		f_dec_and_log(c_gmm_mo_att_req);
+		f_dec_and_log(c_gmm_mt_ac_req);
+		f_dec_and_log(c_gmm_mo_ac_resp);
+		f_dec_and_log(c_gmm_mt_att_acc);
+		f_dec_and_log(c_gmm_mt_det_req);
+		f_dec_and_log(c_gmm_mo_att_cpl);
+	}
+
+	control {
+		execute(TC_selftest());
+	}
+};