selftests: breakpoints: return Kselftest Skip code for skipped tests

When step_after_suspend_test is skipped because of unmet dependencies
and/or unsupported configuration, it exits with error which is treated
as a fail by the Kselftest framework. This leads to false negative result
even when the test could not be run.

Change it to return kselftest skip code when a test gets skipped to clearly
report that the test could not be run.

Change it to use ksft_exit_skip() when a non-root user runs the test and
add an explicit check for root and a clear message, instead of failing
the test when /sys/power/state file open fails.

Signed-off-by: Shuah Khan (Samsung OSG) <shuah@kernel.org>

tools/testing/selftests/breakpoints/step_after_suspend_test.c

@@ -143,10 +143,14 @@ void suspend(void)
 	int err;
 	struct itimerspec spec = {};
 
+	if (getuid() != 0)
+		ksft_exit_skip("Please run the test as root - Exiting.\n");
+
 	power_state_fd = open("/sys/power/state", O_RDWR);
 	if (power_state_fd < 0)
 		ksft_exit_fail_msg(
-			"open(\"/sys/power/state\") failed (is this test running as root?)\n");
+			"open(\"/sys/power/state\") failed %s)\n",
+			strerror(errno));
 
 	timerfd = timerfd_create(CLOCK_BOOTTIME_ALARM, 0);
 	if (timerfd < 0)