[PATCH] Fix: tests: honour LTTNG_TOOLS_DISABLE_KERNEL_TESTS in two Python tests

[OOHehir via lttng-dev <lttng-dev@lists.lttng.org>]

From: OOHehir <oo.hehir@gmail.com>

OBSERVED ISSUE
━━━━━━━━━━━━━━
On a target without lttng-modules, kernel/test_event_disable.py & the
kernel cases of tools/save-load/test_save_load.py fail with "Kernel tracer
not available", although the test run sets LTTNG_TOOLS_DISABLE_KERNEL_TESTS=1.
Observed with the Yocto Project ptest on riscv64, which ships no lttng-modules.

CAUSE
━━━━━
Both scripts only check that they run as root before running kernel cases,
while the other Python tests use lttngtest._Environment.run_kernel_tests(),
which also honours LTTNG_TOOLS_DISABLE_KERNEL_TESTS.

SOLUTION
━━━━━━━━
Use run_kernel_tests() in both scripts. It checks for root as before, & also
honours LTTNG_TOOLS_DISABLE_KERNEL_TESTS.

Signed-off-by: OOHehir <oo.hehir@gmail.com>
---
 tests/regression/kernel/test_event_disable.py      | 7 ++-----
 tests/regression/tools/save-load/test_save_load.py | 9 ++++-----
 2 files changed, 6 insertions(+), 10 deletions(-)

diff --git a/tests/regression/kernel/test_event_disable.py b/tests/regression/kernel/test_event_disable.py
index da9f146..a373544 100755
--- a/tests/regression/kernel/test_event_disable.py
+++ b/tests/regression/kernel/test_event_disable.py
@@ -15,7 +15,6 @@ Validates that disabling events works correctly:
 - Disabling by name disables all matching rules regardless of filters
 """
 
-import os
 import pathlib
 import sys
 import traceback
@@ -307,11 +306,9 @@ if __name__ == "__main__":
         ),
     ]
 
-    is_root = os.getuid() == 0
-
-    if not is_root:
+    if not lttngtest._Environment.run_kernel_tests():
         tap = lttngtest.TapGenerator(len(kernel_tests))
-        tap.skip_all_remaining("Kernel tests require root privileges")
+        tap.skip_all_remaining("Kernel tests not enabled")
         sys.exit(0)
 
     tap = lttngtest.TapGenerator(len(kernel_tests))
diff --git a/tests/regression/tools/save-load/test_save_load.py b/tests/regression/tools/save-load/test_save_load.py
index 9dd8042..1983263 100755
--- a/tests/regression/tools/save-load/test_save_load.py
+++ b/tests/regression/tools/save-load/test_save_load.py
@@ -13,7 +13,6 @@ through save/load cycles, including:
 - Kernel syscalls and tracepoints
 """
 
-import os
 import pathlib
 import sys
 import traceback
@@ -953,11 +952,11 @@ if __name__ == "__main__":
         ),
     ]
 
-    is_root = os.getuid() == 0
+    run_kernel_tests = lttngtest._Environment.run_kernel_tests()
     allows_destructive = lttngtest._Environment.allows_destructive()
 
     total_tests = len(user_tests) + len(agent_tests)
-    if is_root:
+    if run_kernel_tests:
         total_tests += len(kernel_tests)
         if allows_destructive:
             total_tests += len(destructive_kernel_tests)
@@ -971,7 +970,7 @@ if __name__ == "__main__":
         for test_name, test_func, kwargs in agent_tests:
             run_test(tap, test_env, test_func, test_name, **kwargs)
 
-    if is_root:
+    if run_kernel_tests:
         with lttngtest.test_environment(
             with_sessiond=True, log=tap.diagnostic, enable_kernel_domain=True
         ) as test_env:
@@ -986,6 +985,6 @@ if __name__ == "__main__":
                     "Skipping destructive kernel tests (LTTNG_ENABLE_DESTRUCTIVE_TESTS not set)"
                 )
     else:
-        tap.diagnostic("Skipping kernel tests (not running as root)")
+        tap.diagnostic("Skipping kernel tests (not enabled)")
 
     sys.exit(0 if tap.is_successful else 1)
-- 
2.43.0