selftests: mptcp: join: no extra msg if no counter

The checksum and fail counters might not be available. Then no need to
display an extra message with missing info.

While at it, fix the indentation around, which is wrong since the same
commit.

Fixes: 47867f0a ("selftests: mptcp: join: skip check if MIB counter not supported")
Cc: stable@vger.kernel.org
Reviewed-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

tools/testing/selftests/net/mptcp/mptcp_join.sh

@@ -1112,26 +1112,26 @@ chk_csum_nr()
 
 	print_check "sum"
 	count=$(mptcp_lib_get_counter ${ns1} "MPTcpExtDataCsumErr")
-	if [ "$count" != "$csum_ns1" ]; then
+	if [ -n "$count" ] && [ "$count" != "$csum_ns1" ]; then
 		extra_msg+=" ns1=$count"
 	fi
 	if [ -z "$count" ]; then
 		print_skip
 	elif { [ "$count" != $csum_ns1 ] && [ $allow_multi_errors_ns1 -eq 0 ]; } ||
-	   { [ "$count" -lt $csum_ns1 ] && [ $allow_multi_errors_ns1 -eq 1 ]; }; then
+	     { [ "$count" -lt $csum_ns1 ] && [ $allow_multi_errors_ns1 -eq 1 ]; }; then
 		fail_test "got $count data checksum error[s] expected $csum_ns1"
 	else
 		print_ok
 	fi
 	print_check "csum"
 	count=$(mptcp_lib_get_counter ${ns2} "MPTcpExtDataCsumErr")
-	if [ "$count" != "$csum_ns2" ]; then
+	if [ -n "$count" ] && [ "$count" != "$csum_ns2" ]; then
 		extra_msg+=" ns2=$count"
 	fi
 	if [ -z "$count" ]; then
 		print_skip
 	elif { [ "$count" != $csum_ns2 ] && [ $allow_multi_errors_ns2 -eq 0 ]; } ||
-	   { [ "$count" -lt $csum_ns2 ] && [ $allow_multi_errors_ns2 -eq 1 ]; }; then
+	     { [ "$count" -lt $csum_ns2 ] && [ $allow_multi_errors_ns2 -eq 1 ]; }; then
 		fail_test "got $count data checksum error[s] expected $csum_ns2"
 	else
 		print_ok
@@ -1169,13 +1169,13 @@ chk_fail_nr()
 
 	print_check "ftx"
 	count=$(mptcp_lib_get_counter ${ns_tx} "MPTcpExtMPFailTx")
-	if [ "$count" != "$fail_tx" ]; then
+	if [ -n "$count" ] && [ "$count" != "$fail_tx" ]; then
 		extra_msg+=",tx=$count"
 	fi
 	if [ -z "$count" ]; then
 		print_skip
 	elif { [ "$count" != "$fail_tx" ] && [ $allow_tx_lost -eq 0 ]; } ||
-	   { [ "$count" -gt "$fail_tx" ] && [ $allow_tx_lost -eq 1 ]; }; then
+	     { [ "$count" -gt "$fail_tx" ] && [ $allow_tx_lost -eq 1 ]; }; then
 		fail_test "got $count MP_FAIL[s] TX expected $fail_tx"
 	else
 		print_ok
@@ -1183,13 +1183,13 @@ chk_fail_nr()
 
 	print_check "failrx"
 	count=$(mptcp_lib_get_counter ${ns_rx} "MPTcpExtMPFailRx")
-	if [ "$count" != "$fail_rx" ]; then
+	if [ -n "$count" ] && [ "$count" != "$fail_rx" ]; then
 		extra_msg+=",rx=$count"
 	fi
 	if [ -z "$count" ]; then
 		print_skip
 	elif { [ "$count" != "$fail_rx" ] && [ $allow_rx_lost -eq 0 ]; } ||
-	   { [ "$count" -gt "$fail_rx" ] && [ $allow_rx_lost -eq 1 ]; }; then
+	     { [ "$count" -gt "$fail_rx" ] && [ $allow_rx_lost -eq 1 ]; }; then
 		fail_test "got $count MP_FAIL[s] RX expected $fail_rx"
 	else
 		print_ok