[PATCH net-next] selftests: net: py: color the basics in the output

[PATCH net-next] selftests: net: py: color the basics in the output

[Jakub Kicinski]

Sometimes it's hard to spot the ok / not ok lines in the output.
This is especially true for the GRO tests which retries a lot
so there's a wall of non-fatal output printed.

Try to color the crucial lines green / red / yellow when running
in a terminal.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
This is a bit of RFC, I'm not super convinced this is worth
carrying in the tree? Please Ack/Review I'll apply if we get
3 supporting tags.
---
CC: shuah@kernel.org
CC: petrm@nvidia.com
CC: willemb@google.com
CC: linux-kselftest@vger.kernel.org
---
 tools/testing/selftests/net/lib/py/ksft.py | 29 ++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/tools/testing/selftests/net/lib/py/ksft.py b/tools/testing/selftests/net/lib/py/ksft.py
index 28a7a994526d..2a6e9113ef5b 100644
--- a/tools/testing/selftests/net/lib/py/ksft.py
+++ b/tools/testing/selftests/net/lib/py/ksft.py
@@ -4,6 +4,7 @@ import argparse
 import fnmatch
 import functools
 import inspect
+import os
 import signal
 import sys
 import time
@@ -17,6 +18,26 @@ KSFT_RESULT_ALL = True
 KSFT_DISRUPTIVE = True
 
 
+def _ksft_supports_color():
+    if os.environ.get("NO_COLOR") is not None:
+        return False
+    if not hasattr(sys.stdout, "isatty") or not sys.stdout.isatty():
+        return False
+    if os.environ.get("TERM") == "dumb":
+        return False
+    return True
+
+
+_KSFT_COLOR = None
+
+
+def _ksft_color():
+    global _KSFT_COLOR
+    if _KSFT_COLOR is None:
+        _KSFT_COLOR = _ksft_supports_color()
+    return _KSFT_COLOR
+
+
 class KsftFailEx(Exception):
     pass
 
@@ -167,6 +188,14 @@ KSFT_DISRUPTIVE = True
         res += "." + case_name
     if comment:
         res += " # " + comment
+    if _ksft_color():
+        if comment.startswith(("SKIP", "XFAIL")):
+            color = "\033[33m"
+        elif ok:
+            color = "\033[32m"
+        else:
+            color = "\033[31m"
+        res = color + res + "\033[0m"
     print(res, flush=True)
 
 
-- 
2.53.0

Re: [PATCH net-next] selftests: net: py: color the basics in the output

[Stanislav Fomichev]

On 04/01, Jakub Kicinski wrote:
> Sometimes it's hard to spot the ok / not ok lines in the output.
> This is especially true for the GRO tests which retries a lot
> so there's a wall of non-fatal output printed.
> 
> Try to color the crucial lines green / red / yellow when running
> in a terminal.
> 
> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
> ---
> This is a bit of RFC, I'm not super convinced this is worth
> carrying in the tree? Please Ack/Review I'll apply if we get
> 3 supporting tags.

Acked-by: Stanislav Fomichev <sdf@fomichev.me>

(not sure why you think this might be controversial)

Re: [PATCH net-next] selftests: net: py: color the basics in the output

[Jakub Kicinski]

On Wed, 1 Apr 2026 14:29:10 -0700 Stanislav Fomichev wrote:
> (not sure why you think this might be controversial)

I'd like the "libraries" to be minimal, so any increase in LoC has to
strongly justify itself. Whenever I work on something in ksft I tend
to produce a bunch of "improvements" of this sort but usually lose
confidence and don't send them out. The coloring thing has been
annoying me for a while but mostly in NIPA context (on the web).

Re: [PATCH net-next] selftests: net: py: color the basics in the output

[Willem de Bruijn]

Stanislav Fomichev wrote:
> On 04/01, Jakub Kicinski wrote:
> > Sometimes it's hard to spot the ok / not ok lines in the output.
> > This is especially true for the GRO tests which retries a lot
> > so there's a wall of non-fatal output printed.
> > 
> > Try to color the crucial lines green / red / yellow when running
> > in a terminal.
> > 
> > Signed-off-by: Jakub Kicinski <kuba@kernel.org>
> > ---
> > This is a bit of RFC, I'm not super convinced this is worth
> > carrying in the tree? Please Ack/Review I'll apply if we get
> > 3 supporting tags.
> 
> Acked-by: Stanislav Fomichev <sdf@fomichev.me>

Reviewed-by: Willem de Bruijn <willemb@google.com>

Minor aside: I don't know exactly how to exhaustively test whether a
terminal supports colors. If unsure, an inverse approach to err on the
side of caution may be safer. But overall +1 on the intent.

Re: [PATCH net-next] selftests: net: py: color the basics in the output

[Joe Damato]

On Wed, Apr 01, 2026 at 11:33:09AM -0700, Jakub Kicinski wrote:
> Sometimes it's hard to spot the ok / not ok lines in the output.
> This is especially true for the GRO tests which retries a lot
> so there's a wall of non-fatal output printed.
> 
> Try to color the crucial lines green / red / yellow when running
> in a terminal.
> 
> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
> ---
> This is a bit of RFC, I'm not super convinced this is worth
> carrying in the tree? Please Ack/Review I'll apply if we get
> 3 supporting tags.
> ---
> CC: shuah@kernel.org
> CC: petrm@nvidia.com
> CC: willemb@google.com
> CC: linux-kselftest@vger.kernel.org
> ---
>  tools/testing/selftests/net/lib/py/ksft.py | 29 ++++++++++++++++++++++
>  1 file changed, 29 insertions(+)

Colorized output is nice.

Acked-by: Joe Damato <joe@dama.to>