macro_rules! int_module {
    ($T:ident, $T_i:ident) => {
        #[cfg(test)]
        mod tests {
            use core::ops::{BitAnd, BitOr, BitXor, Not, Shl, Shr};
            use core::$T_i::*;

            use crate::num;

            #[test]
            fn test_overflows() {
                assert!(MAX > 0);
                assert!(MIN <= 0);
                assert_eq!(MIN + MAX + 1, 0);
            }

            #[test]
            fn test_num() {
                num::test_num(10 as $T, 2 as $T);
            }

            #[test]
            fn test_rem_euclid() {
                assert_eq!((-1 as $T).rem_euclid(MIN), MAX);
            }

            #[test]
            pub fn test_abs() {
                assert_eq!((1 as $T).abs(), 1 as $T);
                assert_eq!((0 as $T).abs(), 0 as $T);
                assert_eq!((-1 as $T).abs(), 1 as $T);
            }

            #[test]
            fn test_signum() {
                assert_eq!((1 as $T).signum(), 1 as $T);
                assert_eq!((0 as $T).signum(), 0 as $T);
                assert_eq!((-0 as $T).signum(), 0 as $T);
                assert_eq!((-1 as $T).signum(), -1 as $T);
            }

            #[test]
            fn test_is_positive() {
                assert!((1 as $T).is_positive());
                assert!(!(0 as $T).is_positive());
                assert!(!(-0 as $T).is_positive());
                assert!(!(-1 as $T).is_positive());
            }

            #[test]
            fn test_is_negative() {
                assert!(!(1 as $T).is_negative());
                assert!(!(0 as $T).is_negative());
                assert!(!(-0 as $T).is_negative());
                assert!((-1 as $T).is_negative());
            }

            #[test]
            fn test_bitwise_operators() {
                assert_eq!(0b1110 as $T, (0b1100 as $T).bitor(0b1010 as $T));
                assert_eq!(0b1000 as $T, (0b1100 as $T).bitand(0b1010 as $T));
                assert_eq!(0b0110 as $T, (0b1100 as $T).bitxor(0b1010 as $T));
                assert_eq!(0b1110 as $T, (0b0111 as $T).shl(1));
                assert_eq!(0b0111 as $T, (0b1110 as $T).shr(1));
                assert_eq!(-(0b11 as $T) - (1 as $T), (0b11 as $T).not());
            }

            const A: $T = 0b0101100;
            const B: $T = 0b0100001;
            const C: $T = 0b1111001;

            const _0: $T = 0;
            const _1: $T = !0;

            #[test]
            fn test_count_ones() {
                assert_eq!(A.count_ones(), 3);
                assert_eq!(B.count_ones(), 2);
                assert_eq!(C.count_ones(), 5);
            }

            #[test]
            fn test_count_zeros() {
                assert_eq!(A.count_zeros(), $T::BITS - 3);
                assert_eq!(B.count_zeros(), $T::BITS - 2);
                assert_eq!(C.count_zeros(), $T::BITS - 5);
            }

            #[test]
            fn test_leading_trailing_ones() {
                let a: $T = 0b0101_1111;
                assert_eq!(a.trailing_ones(), 5);
                assert_eq!((!a).leading_ones(), $T::BITS - 7);

                assert_eq!(a.reverse_bits().leading_ones(), 5);

                assert_eq!(_1.leading_ones(), $T::BITS);
                assert_eq!(_1.trailing_ones(), $T::BITS);

                assert_eq!((_1 << 1).trailing_ones(), 0);
                assert_eq!(MAX.leading_ones(), 0);

                assert_eq!((_1 << 1).leading_ones(), $T::BITS - 1);
                assert_eq!(MAX.trailing_ones(), $T::BITS - 1);

                assert_eq!(_0.leading_ones(), 0);
                assert_eq!(_0.trailing_ones(), 0);

                let x: $T = 0b0010_1100;
                assert_eq!(x.leading_ones(), 0);
                assert_eq!(x.trailing_ones(), 0);
            }

            #[test]
            fn test_rotate() {
                assert_eq!(A.rotate_left(6).rotate_right(2).rotate_right(4), A);
                assert_eq!(B.rotate_left(3).rotate_left(2).rotate_right(5), B);
                assert_eq!(C.rotate_left(6).rotate_right(2).rotate_right(4), C);

                // Rotating these should make no difference
                //
                // We test using 124 bits because to ensure that overlong bit shifts do
                // not cause undefined behaviour. See #10183.
                assert_eq!(_0.rotate_left(124), _0);
                assert_eq!(_1.rotate_left(124), _1);
                assert_eq!(_0.rotate_right(124), _0);
                assert_eq!(_1.rotate_right(124), _1);

                // Rotating by 0 should have no effect
                assert_eq!(A.rotate_left(0), A);
                assert_eq!(B.rotate_left(0), B);
                assert_eq!(C.rotate_left(0), C);
                // Rotating by a multiple of word size should also have no effect
                assert_eq!(A.rotate_left(64), A);
                assert_eq!(B.rotate_left(64), B);
                assert_eq!(C.rotate_left(64), C);
            }

            #[test]
            fn test_swap_bytes() {
                assert_eq!(A.swap_bytes().swap_bytes(), A);
                assert_eq!(B.swap_bytes().swap_bytes(), B);
                assert_eq!(C.swap_bytes().swap_bytes(), C);

                // Swapping these should make no difference
                assert_eq!(_0.swap_bytes(), _0);
                assert_eq!(_1.swap_bytes(), _1);
            }

            #[test]
            fn test_le() {
                assert_eq!($T::from_le(A.to_le()), A);
                assert_eq!($T::from_le(B.to_le()), B);
                assert_eq!($T::from_le(C.to_le()), C);
                assert_eq!($T::from_le(_0), _0);
                assert_eq!($T::from_le(_1), _1);
                assert_eq!(_0.to_le(), _0);
                assert_eq!(_1.to_le(), _1);
            }

            #[test]
            fn test_be() {
                assert_eq!($T::from_be(A.to_be()), A);
                assert_eq!($T::from_be(B.to_be()), B);
                assert_eq!($T::from_be(C.to_be()), C);
                assert_eq!($T::from_be(_0), _0);
                assert_eq!($T::from_be(_1), _1);
                assert_eq!(_0.to_be(), _0);
                assert_eq!(_1.to_be(), _1);
            }

            #[test]
            fn test_signed_checked_div() {
                assert_eq!((10 as $T).checked_div(2), Some(5));
                assert_eq!((5 as $T).checked_div(0), None);
                assert_eq!(isize::MIN.checked_div(-1), None);
            }

            #[test]
            fn test_saturating_abs() {
                assert_eq!((0 as $T).saturating_abs(), 0);
                assert_eq!((123 as $T).saturating_abs(), 123);
                assert_eq!((-123 as $T).saturating_abs(), 123);
                assert_eq!((MAX - 2).saturating_abs(), MAX - 2);
                assert_eq!((MAX - 1).saturating_abs(), MAX - 1);
                assert_eq!(MAX.saturating_abs(), MAX);
                assert_eq!((MIN + 2).saturating_abs(), MAX - 1);
                assert_eq!((MIN + 1).saturating_abs(), MAX);
                assert_eq!(MIN.saturating_abs(), MAX);
            }

            #[test]
            fn test_saturating_neg() {
                assert_eq!((0 as $T).saturating_neg(), 0);
                assert_eq!((123 as $T).saturating_neg(), -123);
                assert_eq!((-123 as $T).saturating_neg(), 123);
                assert_eq!((MAX - 2).saturating_neg(), MIN + 3);
                assert_eq!((MAX - 1).saturating_neg(), MIN + 2);
                assert_eq!(MAX.saturating_neg(), MIN + 1);
                assert_eq!((MIN + 2).saturating_neg(), MAX - 1);
                assert_eq!((MIN + 1).saturating_neg(), MAX);
                assert_eq!(MIN.saturating_neg(), MAX);
            }

            #[test]
            fn test_from_str() {
                fn from_str<T: ::std::str::FromStr>(t: &str) -> Option<T> {
                    ::std::str::FromStr::from_str(t).ok()
                }
                assert_eq!(from_str::<$T>("0"), Some(0 as $T));
                assert_eq!(from_str::<$T>("3"), Some(3 as $T));
                assert_eq!(from_str::<$T>("10"), Some(10 as $T));
                assert_eq!(from_str::<i32>("123456789"), Some(123456789 as i32));
                assert_eq!(from_str::<$T>("00100"), Some(100 as $T));

                assert_eq!(from_str::<$T>("-1"), Some(-1 as $T));
                assert_eq!(from_str::<$T>("-3"), Some(-3 as $T));
                assert_eq!(from_str::<$T>("-10"), Some(-10 as $T));
                assert_eq!(from_str::<i32>("-123456789"), Some(-123456789 as i32));
                assert_eq!(from_str::<$T>("-00100"), Some(-100 as $T));

                assert_eq!(from_str::<$T>(""), None);
                assert_eq!(from_str::<$T>(" "), None);
                assert_eq!(from_str::<$T>("x"), None);
            }

            #[test]
            fn test_from_str_radix() {
                assert_eq!($T::from_str_radix("123", 10), Ok(123 as $T));
                assert_eq!($T::from_str_radix("1001", 2), Ok(9 as $T));
                assert_eq!($T::from_str_radix("123", 8), Ok(83 as $T));
                assert_eq!(i32::from_str_radix("123", 16), Ok(291 as i32));
                assert_eq!(i32::from_str_radix("ffff", 16), Ok(65535 as i32));
                assert_eq!(i32::from_str_radix("FFFF", 16), Ok(65535 as i32));
                assert_eq!($T::from_str_radix("z", 36), Ok(35 as $T));
                assert_eq!($T::from_str_radix("Z", 36), Ok(35 as $T));

                assert_eq!($T::from_str_radix("-123", 10), Ok(-123 as $T));
                assert_eq!($T::from_str_radix("-1001", 2), Ok(-9 as $T));
                assert_eq!($T::from_str_radix("-123", 8), Ok(-83 as $T));
                assert_eq!(i32::from_str_radix("-123", 16), Ok(-291 as i32));
                assert_eq!(i32::from_str_radix("-ffff", 16), Ok(-65535 as i32));
                assert_eq!(i32::from_str_radix("-FFFF", 16), Ok(-65535 as i32));
                assert_eq!($T::from_str_radix("-z", 36), Ok(-35 as $T));
                assert_eq!($T::from_str_radix("-Z", 36), Ok(-35 as $T));

                assert_eq!($T::from_str_radix("Z", 35).ok(), None::<$T>);
                assert_eq!($T::from_str_radix("-9", 2).ok(), None::<$T>);
            }

            #[test]
            fn test_pow() {
                let mut r = 2 as $T;
                assert_eq!(r.pow(2), 4 as $T);
                assert_eq!(r.pow(0), 1 as $T);
                assert_eq!(r.wrapping_pow(2), 4 as $T);
                assert_eq!(r.wrapping_pow(0), 1 as $T);
                assert_eq!(r.checked_pow(2), Some(4 as $T));
                assert_eq!(r.checked_pow(0), Some(1 as $T));
                assert_eq!(r.overflowing_pow(2), (4 as $T, false));
                assert_eq!(r.overflowing_pow(0), (1 as $T, false));
                assert_eq!(r.saturating_pow(2), 4 as $T);
                assert_eq!(r.saturating_pow(0), 1 as $T);

                r = MAX;
                // use `^` to represent .pow() with no overflow.
                // if itest::MAX == 2^j-1, then itest is a `j` bit int,
                // so that `itest::MAX*itest::MAX == 2^(2*j)-2^(j+1)+1`,
                // thussaturating_pow the overflowing result is exactly 1.
                assert_eq!(r.wrapping_pow(2), 1 as $T);
                assert_eq!(r.checked_pow(2), None);
                assert_eq!(r.overflowing_pow(2), (1 as $T, true));
                assert_eq!(r.saturating_pow(2), MAX);
                //test for negative exponent.
                r = -2 as $T;
                assert_eq!(r.pow(2), 4 as $T);
                assert_eq!(r.pow(3), -8 as $T);
                assert_eq!(r.pow(0), 1 as $T);
                assert_eq!(r.wrapping_pow(2), 4 as $T);
                assert_eq!(r.wrapping_pow(3), -8 as $T);
                assert_eq!(r.wrapping_pow(0), 1 as $T);
                assert_eq!(r.checked_pow(2), Some(4 as $T));
                assert_eq!(r.checked_pow(3), Some(-8 as $T));
                assert_eq!(r.checked_pow(0), Some(1 as $T));
                assert_eq!(r.overflowing_pow(2), (4 as $T, false));
                assert_eq!(r.overflowing_pow(3), (-8 as $T, false));
                assert_eq!(r.overflowing_pow(0), (1 as $T, false));
                assert_eq!(r.saturating_pow(2), 4 as $T);
                assert_eq!(r.saturating_pow(3), -8 as $T);
                assert_eq!(r.saturating_pow(0), 1 as $T);
            }
        }
    };
}
