Thanks to the parent commit, it is easy to change the output and add
some colours to easily spot issues.

The colours are not used if stdout is redirected or if NO_COLOR env var
is set to 1 as specified in https://no-color.org.

Acked-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
---
 tools/testing/selftests/net/mptcp/mptcp_join.sh |  8 +++---
 tools/testing/selftests/net/mptcp/mptcp_lib.sh  | 38 +++++++++++++++++++++++++
 2 files changed, 42 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/net/mptcp/mptcp_join.sh b/tools/testing/selftests/net/mptcp/mptcp_join.sh
index e6bd4816cf74..2f47686b6214 100755
--- a/tools/testing/selftests/net/mptcp/mptcp_join.sh
+++ b/tools/testing/selftests/net/mptcp/mptcp_join.sh
@@ -217,22 +217,22 @@ print_info()
 	# It can be empty, no need to print anything then
 	[ -z "${1}" ] && return
 
-	printf "%-${nr_blank}sInfo: %s\n" " " "${*}"
+	mptcp_lib_print_info "      Info: ${*}"
 }
 
 print_ok()
 {
-	echo "[ ok ]${1:+ ${*}}"
+	mptcp_lib_print_ok "[ ok ]${1:+ ${*}}"
 }
 
 print_fail()
 {
-	echo "[fail]${1:+ ${*}}"
+	mptcp_lib_print_err "[fail]${1:+ ${*}}"
 }
 
 print_skip()
 {
-	echo "[skip]${1:+ ${*}}"
+	mptcp_lib_print_warn "[skip]${1:+ ${*}}"
 }
 
 # [ $1: fail msg ]
diff --git a/tools/testing/selftests/net/mptcp/mptcp_lib.sh b/tools/testing/selftests/net/mptcp/mptcp_lib.sh
index b1a0fdd0408b..1080d5d2430b 100644
--- a/tools/testing/selftests/net/mptcp/mptcp_lib.sh
+++ b/tools/testing/selftests/net/mptcp/mptcp_lib.sh
@@ -4,10 +4,48 @@
 readonly KSFT_PASS=0
 readonly KSFT_FAIL=1
 readonly KSFT_SKIP=4
+
+# shellcheck disable=SC2155 # declare and assign separately
 readonly KSFT_TEST=$(basename "${0}" | sed 's/\.sh$//g')
 
 MPTCP_LIB_SUBTESTS=()
 
+# only if supported and not disabled, see no-color.org
+if [ -t 1 ] && [ "${NO_COLOR:-}" != "1" ]; then
+	readonly MPTCP_LIB_COLOR_RED="\E[1;31m"
+	readonly MPTCP_LIB_COLOR_GREEN="\E[1;32m"
+	readonly MPTCP_LIB_COLOR_YELLOW="\E[1;33m"
+	readonly MPTCP_LIB_COLOR_BLUE="\E[1;34m"
+	readonly MPTCP_LIB_COLOR_RESET="\E[0m"
+else
+	readonly MPTCP_LIB_COLOR_RED=
+	readonly MPTCP_LIB_COLOR_GREEN=
+	readonly MPTCP_LIB_COLOR_YELLOW=
+	readonly MPTCP_LIB_COLOR_BLUE=
+	readonly MPTCP_LIB_COLOR_RESET=
+fi
+
+# $1: color, $2: text
+mptcp_lib_print_color() {
+	echo -e "${MPTCP_LIB_START_PRINT:-}${*}${MPTCP_LIB_COLOR_RESET}"
+}
+
+mptcp_lib_print_ok() {
+	mptcp_lib_print_color "${MPTCP_LIB_COLOR_GREEN}${*}"
+}
+
+mptcp_lib_print_warn() {
+	mptcp_lib_print_color "${MPTCP_LIB_COLOR_YELLOW}${*}"
+}
+
+mptcp_lib_print_info() {
+	mptcp_lib_print_color "${MPTCP_LIB_COLOR_BLUE}${*}"
+}
+
+mptcp_lib_print_err() {
+	mptcp_lib_print_color "${MPTCP_LIB_COLOR_RED}${*}"
+}
+
 # SELFTESTS_MPTCP_LIB_EXPECT_ALL_FEATURES env var can be set when validating all
 # features using the last version of the kernel and the selftests to make sure
 # a test is not being skipped by mistake.

-- 
2.40.1