[PATCH] selftests/ftrace: Use colored output when available

[Daniel Díaz <daniel.diaz@xxxxxxxxxx>]

If test is being directly executed (with stdout opened on the
terminal) and the terminal capabilities indicate enough
colors, then use the existing scheme of green, red, and blue
to show when tests pass, fail or end in a different way.

When running the tests redirecting the stdout, for instance,
to a file, then colors are not shown, thus producing a more
readable output.

Signed-off-by: Daniel Díaz <daniel.diaz@xxxxxxxxxx>
---
 tools/testing/selftests/ftrace/ftracetest | 29 +++++++++++++++++------
 1 file changed, 22 insertions(+), 7 deletions(-)

diff --git a/tools/testing/selftests/ftrace/ftracetest b/tools/testing/selftests/ftrace/ftracetest
index 4946b2edfcff..d987bbec675f 100755
--- a/tools/testing/selftests/ftrace/ftracetest
+++ b/tools/testing/selftests/ftrace/ftracetest
@@ -152,6 +152,21 @@ else
   date > $LOG_FILE
 fi
 
+# Define text colors
+# Check available colors on the terminal, if any
+ncolors=`tput colors 2>/dev/null`
+color_reset=
+color_red=
+color_green=
+color_blue=
+# If stdout exists and number of colors is eight or more, use them
+if [ -t 1 -a "$ncolors" -a "$ncolors" -ge 8 ]; then
+  color_reset="\e[0m"
+  color_red="\e[31m"
+  color_green="\e[32m"
+  color_blue="\e[34m"
+fi
+
 prlog() { # messages
   [ -z "$LOG_FILE" ] && echo -e "$@" || echo -e "$@" | tee -a $LOG_FILE
 }
@@ -195,37 +210,37 @@ test_on_instance() { # testfile
 eval_result() { # sigval
   case $1 in
     $PASS)
-      prlog "	[\e[32mPASS\e[30m]"
+      prlog "	[${color_green}PASS${color_reset}]"
       PASSED_CASES="$PASSED_CASES $CASENO"
       return 0
     ;;
     $FAIL)
-      prlog "	[\e[31mFAIL\e[30m]"
+      prlog "	[${color_red}FAIL${color_reset}]"
       FAILED_CASES="$FAILED_CASES $CASENO"
       return 1 # this is a bug.
     ;;
     $UNRESOLVED)
-      prlog "	[\e[34mUNRESOLVED\e[30m]"
+      prlog "	[${color_blue}UNRESOLVED${color_reset}]"
       UNRESOLVED_CASES="$UNRESOLVED_CASES $CASENO"
       return 1 # this is a kind of bug.. something happened.
     ;;
     $UNTESTED)
-      prlog "	[\e[34mUNTESTED\e[30m]"
+      prlog "	[${color_blue}UNTESTED${color_reset}]"
       UNTESTED_CASES="$UNTESTED_CASES $CASENO"
       return 0
     ;;
     $UNSUPPORTED)
-      prlog "	[\e[34mUNSUPPORTED\e[30m]"
+      prlog "	[${color_blue}UNSUPPORTED${color_reset}]"
       UNSUPPORTED_CASES="$UNSUPPORTED_CASES $CASENO"
       return $UNSUPPORTED_RESULT # depends on use case
     ;;
     $XFAIL)
-      prlog "	[\e[31mXFAIL\e[30m]"
+      prlog "	[${color_red}XFAIL${color_reset}]"
       XFAILED_CASES="$XFAILED_CASES $CASENO"
       return 0
     ;;
     *)
-      prlog "	[\e[34mUNDEFINED\e[30m]"
+      prlog "	[${color_blue}UNDEFINED${color_reset}]"
       UNDEFINED_CASES="$UNDEFINED_CASES $CASENO"
       return 1 # this must be a test bug
     ;;
-- 
2.17.1