tests: posix: Add CLOCK_THREAD_CPUTIME_ID unittest

Added test for 'clock_gettime(CLOCK_THREAD_CPUTIME_ID, &ts)'.

Signed-off-by: James Roy <[email protected]>

tests/posix/common/src/clock.c

@@ -22,10 +22,16 @@ static const struct timespec ref_ts = {1514821501, NSEC_PER_SEC / 2U};
 static const clockid_t clocks[] = {
 	CLOCK_MONOTONIC,
 	CLOCK_REALTIME,
+#ifdef CONFIG_POSIX_THREAD_CPUTIME
+	CLOCK_THREAD_CPUTIME_ID,
+#endif /* CONFIG_POSIX_THREAD_CPUTIME */
 };
 static const bool settable[] = {
 	false,
 	true,
+#ifdef CONFIG_POSIX_THREAD_CPUTIME
+	false,
+#endif /* CONFIG_POSIX_THREAD_CPUTIME */
 };
 
 static inline int64_t ts_to_ns(const struct timespec *ts)
@@ -105,6 +111,9 @@ ZTEST(clock, test_gettimeofday)
 	/* Validate gettimeofday API */
 	zassert_ok(gettimeofday(&tv, NULL));
 	zassert_ok(clock_gettime(CLOCK_REALTIME, &rts));
+#ifdef CONFIG_POSIX_THREAD_CPUTIME
+	zassert_ok(clock_gettime(CLOCK_THREAD_CPUTIME_ID, &ts));
+#endif /* CONFIG_POSIX_THREAD_CPUTIME */
 
 	/* TESTPOINT: Check if time obtained from
 	 * gettimeofday is same or more than obtained