lapd/test: Check for empty ACCH queue, too

This just adds a single test to verify that the ACCH queue is
actually empty.

Sponsored-by: On-Waves ehf
diff --git a/tests/lapd/lapd_test.c b/tests/lapd/lapd_test.c
index e3d4e80..6b5cfd3 100644
--- a/tests/lapd/lapd_test.c
+++ b/tests/lapd/lapd_test.c
@@ -405,6 +405,8 @@
 	/* verify that there is nothing more to poll */
 	rc = dequeue_prim(&bts_to_ms_channel.lapdm_dcch, &pp, "DCCH");
 	OSMO_ASSERT(rc < 0);
+	rc = dequeue_prim(&bts_to_ms_channel.lapdm_acch, &pp, "ACCH");
+	OSMO_ASSERT(rc < 0);
 
 	/* check sending an empty L3 message fails */
 	rc = lapdm_rslms_recvmsg(create_empty_msg(), &bts_to_ms_channel);