selftests: mptcp: add mptcp_lib_check_output helper

Extract the main part of check() in pm_netlink.sh into a new helper
named mptcp_lib_check_output in mptcp_lib.sh.

This helper will be used for userspace dump addresses tests.

Co-developed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 23 insertions, 0 deletions

diff --git a/tools/testing/selftests/net/mptcp/mptcp_lib.sh b/tools/testing/selftests/net/mptcp/mptcp_lib.sh
index 108a1e12436c..438f557aac90 100644
--- a/tools/testing/selftests/net/mptcp/mptcp_lib.sh
+++ b/tools/testing/selftests/net/mptcp/mptcp_lib.sh
@@ -319,3 +319,26 @@ mptcp_lib_wait_local_port_listen() {
 		sleep 0.1
 	done
 }
+
+mptcp_lib_check_output() {
+	local err="${1}"
+	local cmd="${2}"
+	local expected="${3}"
+	local cmd_ret=0
+	local out
+
+	if ! out=$(${cmd} 2>"${err}"); then
+		cmd_ret=${?}
+	fi
+
+	if [ ${cmd_ret} -ne 0 ]; then
+		mptcp_lib_print_err "[FAIL] command execution '${cmd}' stderr"
+		cat "${err}"
+		return 2
+	elif [ "${out}" = "${expected}" ]; then
+		return 0
+	else
+		mptcp_lib_print_err "[FAIL] expected '${expected}' got '${out}'"
+		return 1
+	fi
+}