assert_eq!(r.saturating_pow(2), MAX);
}
+ #[test]
+ fn test_isqrt() {
+ assert_eq!((0 as $T).isqrt(), 0 as $T);
+ assert_eq!((1 as $T).isqrt(), 1 as $T);
+ assert_eq!((2 as $T).isqrt(), 1 as $T);
+ assert_eq!((99 as $T).isqrt(), 9 as $T);
+ assert_eq!((100 as $T).isqrt(), 10 as $T);
+ assert_eq!($T::MAX.isqrt(), (1 << ($T::BITS / 2)) - 1);
+ }
+
+ #[cfg(not(miri))] // Miri is too slow
+ #[test]
+ fn test_lots_of_isqrt() {
+ let n_max: $T = (1024 * 1024).min($T::MAX as u128) as $T;
+ for n in 0..=n_max {
+ let isqrt: $T = n.isqrt();
+
+ assert!(isqrt.pow(2) <= n);
+ assert!(isqrt + 1 == (1 as $T) << ($T::BITS / 2) || (isqrt + 1).pow(2) > n);
+ }
+
+ for n in ($T::MAX - 255)..=$T::MAX {
+ let isqrt: $T = n.isqrt();
+
+ assert!(isqrt.pow(2) <= n);
+ assert!(isqrt + 1 == (1 as $T) << ($T::BITS / 2) || (isqrt + 1).pow(2) > n);
+ }
+ }
+
#[test]
fn test_div_floor() {
assert_eq!((8 as $T).div_floor(3), 2);