selftests: net: set the exit code correctly in Python tests

Test cases need to exit with non-zero status if they failed,
we currently don't do that:

  # KTAP version 1
  # 1..3
  # # At /root/ksft-net-drv/drivers/net/./ping.py line 18:
  # # Check failed 1 != 2
  # not ok 1 ping.test_v4
  # ok 2 ping.test_v6
  # ok 3 ping.test_tcp
  # # Totals: pass:2 fail:1 xfail:0 xpass:0 skip:0 error:0
  ok 1 selftests: drivers/net: ping.py
  ^^^^

It's a bit tempting to make the exit part of ksft_run(),
but that only works well for very trivial setups. We can
revisit this later, if people forget to call ksft_exit().

Link: https://lore.kernel.org/r/20240417231146.2435572-3-kuba@kernel.orgSigned-off-by: Jakub Kicinski <kuba@kernel.org>

tools/testing/selftests/drivers/net/stats.py

 #!/usr/bin/env python3
 # SPDX-License-Identifier: GPL-2.0
 
-from lib.py import ksft_run, ksft_in, ksft_true, KsftSkipEx, KsftXfailEx
+from lib.py import ksft_run, ksft_exit
+from lib.py import ksft_in, ksft_true, KsftSkipEx, KsftXfailEx
 from lib.py import EthtoolFamily, NetdevFamily, RtnlFamily, NlError
 from lib.py import NetDrvEnv
 
@@ -80,6 +81,7 @@ def main() -> None:
     with NetDrvEnv(__file__) as cfg:
         ksft_run([check_pause, check_fec, pkt_byte_sum],
                  args=(cfg, ))
+    ksft_exit()
 
 
 if __name__ == "__main__":

tools/testing/selftests/net/lib/py/ksft.py

@@ -2,11 +2,13 @@
 
 import builtins
 import inspect
+import sys
 import time
 import traceback
 from .consts import KSFT_MAIN_NAME
 
 KSFT_RESULT = None
+KSFT_RESULT_ALL = True
 
 
 class KsftSkipEx(Exception):
@@ -63,6 +65,9 @@ def ksft_busy_wait(cond, sleep=0.005, deadline=1, comment=""):
 
 
 def ktap_result(ok, cnt=1, case="", comment=""):
+    global KSFT_RESULT_ALL
+    KSFT_RESULT_ALL = KSFT_RESULT_ALL and ok
+
     res = ""
     if not ok:
         res += "not "
@@ -114,3 +119,8 @@ def ksft_run(cases, args=()):
     print(
         f"# Totals: pass:{totals['pass']} fail:{totals['fail']} xfail:{totals['xfail']} xpass:0 skip:{totals['skip']} error:0"
     )
+
+
+def ksft_exit():
+    global KSFT_RESULT_ALL
+    sys.exit(0 if KSFT_RESULT_ALL else 1)

tools/testing/selftests/net/nl_netdev.py

@@ -2,7 +2,8 @@
 # SPDX-License-Identifier: GPL-2.0
 
 import time
-from lib.py import ksft_run, ksft_pr, ksft_eq, ksft_ge, ksft_busy_wait
+from lib.py import ksft_run, ksft_exit, ksft_pr
+from lib.py import ksft_eq, ksft_ge, ksft_busy_wait
 from lib.py import NetdevFamily, NetdevSimDev, ip
 
 
@@ -90,6 +91,7 @@ def main() -> None:
     nf = NetdevFamily()
     ksft_run([empty_check, lo_check, page_pool_check],
              args=(nf, ))
+    ksft_exit()
 
 
 if __name__ == "__main__":