VLR tests: use msgb_eq_data_print() for comparison

This simplifies tests refactoring by showing exact byte where mismatch
happened. It also makes code more readable.

No changes in expected test output are necessary because the additional
logging will be triggered iff the test fails so the result will be
visible only during debugging of unit test issues.

Change-Id: If9771c973f2bc55580f4c146bdbeeb1609d56786
diff --git a/tests/msc_vlr/msc_vlr_tests.c b/tests/msc_vlr/msc_vlr_tests.c
index 296f055..eb6df09 100644
--- a/tests/msc_vlr/msc_vlr_tests.c
+++ b/tests/msc_vlr/msc_vlr_tests.c
@@ -570,15 +570,21 @@
 int __real_osmo_gsup_client_send(struct osmo_gsup_client *gsupc, struct msgb *msg);
 int __wrap_osmo_gsup_client_send(struct osmo_gsup_client *gsupc, struct msgb *msg)
 {
-	const char *is = osmo_hexdump_nospc(msg->data, msg->len);
+	uint8_t buf[512];
+	int len;
+
 	fprintf(stderr, "GSUP --> HLR: %s: %s\n",
-		osmo_gsup_message_type_name(msg->data[0]), is);
+		osmo_gsup_message_type_name(msg->data[0]), osmo_hexdump_nospc(msg->data, msg->len));
 
 	OSMO_ASSERT(gsup_tx_expected);
-	if (strcmp(gsup_tx_expected, is)) {
-		fprintf(stderr, "Mismatch! Expected:\n%s\n", gsup_tx_expected);
+	OSMO_ASSERT(strlen(gsup_tx_expected) <= (sizeof(buf) * 2));
+
+	len = osmo_hexparse(gsup_tx_expected, buf, sizeof(buf));
+	if (len < 1)
 		abort();
-	}
+
+	if (!msgb_eq_data_print(msg, buf, len))
+		abort();
 
 	talloc_free(msg);
 	gsup_tx_confirmed = true;
@@ -596,13 +602,8 @@
 
 	/* Mask the sequence number out before comparing */
 	msg->data[1] &= 0x3f;
-	if (msg->len != dtap_tx_expected->len
-	    || memcmp(msg->data, dtap_tx_expected->data, msg->len)) {
-		fprintf(stderr, "Mismatch! Expected:\n%s\n",
-		       osmo_hexdump_nospc(dtap_tx_expected->data,
-					  dtap_tx_expected->len));
+	if (!msgb_eq_data_print(msg, dtap_tx_expected->data, dtap_tx_expected->len))
 		abort();
-	}
 
 	btw("DTAP matches expected message");