selftests: mptcp: userspace: print error details if any

Before, only '[FAIL]' was printed in case of error during the validation
phase.

Now, in case of failure, the variable name, its value and expected one
are displayed to help understand what was wrong.
Reviewed-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NMatthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>

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

@@ -201,11 +201,16 @@ make_connection()
 	server_serverside=$(grep "type:1," "$server_evts" |
 			    sed --unbuffered -n 's/.*\(server_side:\)\([[:digit:]]*\).*$/\2/p;q')
 
+	stdbuf -o0 -e0 printf "Established IP%s MPTCP Connection ns2 => ns1    \t\t" $is_v6
 	if [ "$client_token" != "" ] && [ "$server_token" != "" ] && [ "$client_serverside" = 0 ] &&
 		   [ "$server_serverside" = 1 ]
 	then
-		stdbuf -o0 -e0 printf "Established IP%s MPTCP Connection ns2 => ns1    \t\t[OK]\n" $is_v6
+		stdbuf -o0 -e0 printf "[OK]\n"
 	else
+		stdbuf -o0 -e0 printf "[FAIL]\n"
+		stdbuf -o0 -e0 printf "\tExpected tokens (c:%s - s:%s) and server (c:%d - s:%d)\n" \
+			"${client_token}" "${server_token}" \
+			"${client_serverside}" "${server_serverside}"
 		exit 1
 	fi
 
@@ -225,13 +230,26 @@ make_connection()
 	fi
 }
 
-# $1: var name
+# $1: var name ; $2: prev ret
 check_expected_one()
 {
 	local var="${1}"
 	local exp="e_${var}"
+	local prev_ret="${2}"
 
-	[ "${!var}" = "${!exp}" ]
+	if [ "${!var}" = "${!exp}" ]
+	then
+		return 0
+	fi
+
+	if [ "${prev_ret}" = "0" ]
+	then
+		stdbuf -o0 -e0 printf "[FAIL]\n"
+	fi
+
+	stdbuf -o0 -e0 printf "\tExpected value for '%s': '%s', got '%s'.\n" \
+		"${var}" "${!var}" "${!exp}"
+	return 1
 }
 
 # $@: all var names to check
@@ -242,7 +260,7 @@ check_expected()
 
 	for var in "${@}"
 	do
-		check_expected_one "${var}" || ret=1
+		check_expected_one "${var}" "${ret}" || ret=1
 	done
 
 	if [ ${ret} -eq 0 ]
@@ -251,7 +269,6 @@ check_expected()
 		return 0
 	fi
 
-	stdbuf -o0 -e0 printf "[FAIL]\n"
 	exit 1
 }
 
@@ -303,7 +320,7 @@ test_announce()
 	then
 		stdbuf -o0 -e0 printf "[OK]\n"
 	else
-		stdbuf -o0 -e0 printf "[FAIL]\n"
+		stdbuf -o0 -e0 printf "[FAIL]\n\ttype defined: %s\n" "${type}"
 		exit 1
 	fi
 
@@ -837,7 +854,7 @@ test_prio()
 	count=$(ip netns exec "$ns2" nstat -as | grep MPTcpExtMPPrioTx | awk '{print $2}')
 	[ -z "$count" ] && count=0
 	if [ $count != 1 ]; then
-		stdbuf -o0 -e0 printf "[FAIL]\n"
+		stdbuf -o0 -e0 printf "[FAIL]\n\tCount != 1: %d\n" "${count}"
 		exit 1
 	else
 		stdbuf -o0 -e0 printf "[OK]\n"
@@ -848,7 +865,7 @@ test_prio()
 	count=$(ip netns exec "$ns1" nstat -as | grep MPTcpExtMPPrioRx | awk '{print $2}')
 	[ -z "$count" ] && count=0
 	if [ $count != 1 ]; then
-		stdbuf -o0 -e0 printf "[FAIL]\n"
+		stdbuf -o0 -e0 printf "[FAIL]\n\tCount != 1: %d\n" "${count}"
 		exit 1
 	else
 		stdbuf -o0 -e0 printf "[OK]\n"