test(library): add feature in lib file; fix overflow test; add assert_eq for FROM_NANOS_U128

Author: actuallylost

library/coretests/tests/lib.rs

@@ -37,6 +37,7 @@
 #![feature(duration_constants)]
 #![feature(duration_constructors)]
 #![feature(duration_constructors_lite)]
+#![feature(duration_from_nanos_u128)]
 #![feature(error_generic_member_access)]
 #![feature(exact_div)]
 #![feature(exact_size_is_empty)]

library/coretests/tests/time.rs

@@ -48,7 +48,7 @@ fn from_weeks_overflow() {
 #[test]
 #[should_panic]
 fn from_nanos_u128_overflow() {
-    let overflow = (u64::MAX * NANOS_PER_SEC) + (NANOS_PER_SEC - 1) + 1;
+    let overflow = (u64::MAX as u128 * 1_000_000_000) + (1_000_000_000 - 1) + 1;
     let _ = Duration::from_nanos_u128(overflow);
 }
 
@@ -535,6 +535,9 @@ fn duration_const() {
     const FROM_NANOS: Duration = Duration::from_nanos(1_000_000_000);
     assert_eq!(FROM_NANOS, Duration::SECOND);
 
+    const FROM_NANOS_U128: Duration = Duration::from_nanos_u128(NANOS);
+    assert_eq!(FROM_NANOS_U128, Duration::SECOND);
+
     const MAX: Duration = Duration::new(u64::MAX, 999_999_999);
 
     const CHECKED_ADD: Option<Duration> = MAX.checked_add(Duration::SECOND);