library/std/src/num/tests.rs

   1 use crate::ops::Mul;
   2
   3 #[test]
   4 fn test_saturating_add_uint() {
   5     assert_eq!(3_usize.saturating_add(5_usize), 8_usize);
   6     assert_eq!(3_usize.saturating_add(usize::MAX - 1), usize::MAX);
   7     assert_eq!(usize::MAX.saturating_add(usize::MAX), usize::MAX);
   8     assert_eq!((usize::MAX - 2).saturating_add(1), usize::MAX - 1);
   9 }
  10
  11 #[test]
  12 fn test_saturating_sub_uint() {
  13     assert_eq!(5_usize.saturating_sub(3_usize), 2_usize);
  14     assert_eq!(3_usize.saturating_sub(5_usize), 0_usize);
  15     assert_eq!(0_usize.saturating_sub(1_usize), 0_usize);
  16     assert_eq!((usize::MAX - 1).saturating_sub(usize::MAX), 0);
  17 }
  18
  19 #[test]
  20 fn test_saturating_add_int() {
  21     assert_eq!(3i32.saturating_add(5), 8);
  22     assert_eq!(3isize.saturating_add(isize::MAX - 1), isize::MAX);
  23     assert_eq!(isize::MAX.saturating_add(isize::MAX), isize::MAX);
  24     assert_eq!((isize::MAX - 2).saturating_add(1), isize::MAX - 1);
  25     assert_eq!(3i32.saturating_add(-5), -2);
  26     assert_eq!(isize::MIN.saturating_add(-1), isize::MIN);
  27     assert_eq!((-2isize).saturating_add(-isize::MAX), isize::MIN);
  28 }
  29
  30 #[test]
  31 fn test_saturating_sub_int() {
  32     assert_eq!(3i32.saturating_sub(5), -2);
  33     assert_eq!(isize::MIN.saturating_sub(1), isize::MIN);
  34     assert_eq!((-2isize).saturating_sub(isize::MAX), isize::MIN);
  35     assert_eq!(3i32.saturating_sub(-5), 8);
  36     assert_eq!(3isize.saturating_sub(-(isize::MAX - 1)), isize::MAX);
  37     assert_eq!(isize::MAX.saturating_sub(-isize::MAX), isize::MAX);
  38     assert_eq!((isize::MAX - 2).saturating_sub(-1), isize::MAX - 1);
  39 }
  40
  41 #[test]
  42 fn test_checked_add() {
  43     let five_less = usize::MAX - 5;
  44     assert_eq!(five_less.checked_add(0), Some(usize::MAX - 5));
  45     assert_eq!(five_less.checked_add(1), Some(usize::MAX - 4));
  46     assert_eq!(five_less.checked_add(2), Some(usize::MAX - 3));
  47     assert_eq!(five_less.checked_add(3), Some(usize::MAX - 2));
  48     assert_eq!(five_less.checked_add(4), Some(usize::MAX - 1));
  49     assert_eq!(five_less.checked_add(5), Some(usize::MAX));
  50     assert_eq!(five_less.checked_add(6), None);
  51     assert_eq!(five_less.checked_add(7), None);
  52 }
  53
  54 #[test]
  55 fn test_checked_sub() {
  56     assert_eq!(5_usize.checked_sub(0), Some(5));
  57     assert_eq!(5_usize.checked_sub(1), Some(4));
  58     assert_eq!(5_usize.checked_sub(2), Some(3));
  59     assert_eq!(5_usize.checked_sub(3), Some(2));
  60     assert_eq!(5_usize.checked_sub(4), Some(1));
  61     assert_eq!(5_usize.checked_sub(5), Some(0));
  62     assert_eq!(5_usize.checked_sub(6), None);
  63     assert_eq!(5_usize.checked_sub(7), None);
  64 }
  65
  66 #[test]
  67 fn test_checked_mul() {
  68     let third = usize::MAX / 3;
  69     assert_eq!(third.checked_mul(0), Some(0));
  70     assert_eq!(third.checked_mul(1), Some(third));
  71     assert_eq!(third.checked_mul(2), Some(third * 2));
  72     assert_eq!(third.checked_mul(3), Some(third * 3));
  73     assert_eq!(third.checked_mul(4), None);
  74 }
  75
  76 macro_rules! test_is_power_of_two {
  77     ($test_name:ident, $T:ident) => {
  78         #[test]
  79         fn $test_name() {
  80             assert_eq!((0 as $T).is_power_of_two(), false);
  81             assert_eq!((1 as $T).is_power_of_two(), true);
  82             assert_eq!((2 as $T).is_power_of_two(), true);
  83             assert_eq!((3 as $T).is_power_of_two(), false);
  84             assert_eq!((4 as $T).is_power_of_two(), true);
  85             assert_eq!((5 as $T).is_power_of_two(), false);
  86             assert_eq!(($T::MAX / 2 + 1).is_power_of_two(), true);
  87         }
  88     };
  89 }
  90
  91 test_is_power_of_two! { test_is_power_of_two_u8, u8 }
  92 test_is_power_of_two! { test_is_power_of_two_u16, u16 }
  93 test_is_power_of_two! { test_is_power_of_two_u32, u32 }
  94 test_is_power_of_two! { test_is_power_of_two_u64, u64 }
  95 test_is_power_of_two! { test_is_power_of_two_uint, usize }
  96
  97 macro_rules! test_next_power_of_two {
  98     ($test_name:ident, $T:ident) => {
  99         #[test]
 100         fn $test_name() {
 101             assert_eq!((0 as $T).next_power_of_two(), 1);
 102             let mut next_power = 1;
 103             for i in 1 as $T..40 {
 104                 assert_eq!(i.next_power_of_two(), next_power);
 105                 if i == next_power {
 106                     next_power *= 2
 107                 }
 108             }
 109         }
 110     };
 111 }
 112
 113 test_next_power_of_two! { test_next_power_of_two_u8, u8 }
 114 test_next_power_of_two! { test_next_power_of_two_u16, u16 }
 115 test_next_power_of_two! { test_next_power_of_two_u32, u32 }
 116 test_next_power_of_two! { test_next_power_of_two_u64, u64 }
 117 test_next_power_of_two! { test_next_power_of_two_uint, usize }
 118
 119 macro_rules! test_checked_next_power_of_two {
 120     ($test_name:ident, $T:ident) => {
 121         #[test]
 122         fn $test_name() {
 123             assert_eq!((0 as $T).checked_next_power_of_two(), Some(1));
 124             let smax = $T::MAX >> 1;
 125             assert_eq!(smax.checked_next_power_of_two(), Some(smax + 1));
 126             assert_eq!((smax + 1).checked_next_power_of_two(), Some(smax + 1));
 127             assert_eq!((smax + 2).checked_next_power_of_two(), None);
 128             assert_eq!(($T::MAX - 1).checked_next_power_of_two(), None);
 129             assert_eq!($T::MAX.checked_next_power_of_two(), None);
 130             let mut next_power = 1;
 131             for i in 1 as $T..40 {
 132                 assert_eq!(i.checked_next_power_of_two(), Some(next_power));
 133                 if i == next_power {
 134                     next_power *= 2
 135                 }
 136             }
 137         }
 138     };
 139 }
 140
 141 test_checked_next_power_of_two! { test_checked_next_power_of_two_u8, u8 }
 142 test_checked_next_power_of_two! { test_checked_next_power_of_two_u16, u16 }
 143 test_checked_next_power_of_two! { test_checked_next_power_of_two_u32, u32 }
 144 test_checked_next_power_of_two! { test_checked_next_power_of_two_u64, u64 }
 145 test_checked_next_power_of_two! { test_checked_next_power_of_two_uint, usize }
 146
 147 #[test]
 148 fn test_pow() {
 149     fn naive_pow<T: Mul<Output = T> + Copy>(one: T, base: T, exp: usize) -> T {
 150         (0..exp).fold(one, |acc, _| acc * base)
 151     }
 152     macro_rules! assert_pow {
 153         (($num:expr, $exp:expr) => $expected:expr) => {{
 154             let result = $num.pow($exp);
 155             assert_eq!(result, $expected);
 156             assert_eq!(result, naive_pow(1, $num, $exp));
 157         }};
 158     }
 159     assert_pow!((3u32,     0 ) => 1);
 160     assert_pow!((5u32,     1 ) => 5);
 161     assert_pow!((-4i32,    2 ) => 16);
 162     assert_pow!((8u32,     3 ) => 512);
 163     assert_pow!((2u64,     50) => 1125899906842624);
 164 }
 165
 166 #[test]
 167 fn test_uint_to_str_overflow() {
 168     let mut u8_val: u8 = 255;
 169     assert_eq!(u8_val.to_string(), "255");
 170
 171     u8_val = u8_val.wrapping_add(1);
 172     assert_eq!(u8_val.to_string(), "0");
 173
 174     let mut u16_val: u16 = 65_535;
 175     assert_eq!(u16_val.to_string(), "65535");
 176
 177     u16_val = u16_val.wrapping_add(1);
 178     assert_eq!(u16_val.to_string(), "0");
 179
 180     let mut u32_val: u32 = 4_294_967_295;
 181     assert_eq!(u32_val.to_string(), "4294967295");
 182
 183     u32_val = u32_val.wrapping_add(1);
 184     assert_eq!(u32_val.to_string(), "0");
 185
 186     let mut u64_val: u64 = 18_446_744_073_709_551_615;
 187     assert_eq!(u64_val.to_string(), "18446744073709551615");
 188
 189     u64_val = u64_val.wrapping_add(1);
 190     assert_eq!(u64_val.to_string(), "0");
 191 }
 192
 193 fn from_str<T: crate::str::FromStr>(t: &str) -> Option<T> {
 194     crate::str::FromStr::from_str(t).ok()
 195 }
 196
 197 #[test]
 198 fn test_uint_from_str_overflow() {
 199     let mut u8_val: u8 = 255;
 200     assert_eq!(from_str::<u8>("255"), Some(u8_val));
 201     assert_eq!(from_str::<u8>("256"), None);
 202
 203     u8_val = u8_val.wrapping_add(1);
 204     assert_eq!(from_str::<u8>("0"), Some(u8_val));
 205     assert_eq!(from_str::<u8>("-1"), None);
 206
 207     let mut u16_val: u16 = 65_535;
 208     assert_eq!(from_str::<u16>("65535"), Some(u16_val));
 209     assert_eq!(from_str::<u16>("65536"), None);
 210
 211     u16_val = u16_val.wrapping_add(1);
 212     assert_eq!(from_str::<u16>("0"), Some(u16_val));
 213     assert_eq!(from_str::<u16>("-1"), None);
 214
 215     let mut u32_val: u32 = 4_294_967_295;
 216     assert_eq!(from_str::<u32>("4294967295"), Some(u32_val));
 217     assert_eq!(from_str::<u32>("4294967296"), None);
 218
 219     u32_val = u32_val.wrapping_add(1);
 220     assert_eq!(from_str::<u32>("0"), Some(u32_val));
 221     assert_eq!(from_str::<u32>("-1"), None);
 222
 223     let mut u64_val: u64 = 18_446_744_073_709_551_615;
 224     assert_eq!(from_str::<u64>("18446744073709551615"), Some(u64_val));
 225     assert_eq!(from_str::<u64>("18446744073709551616"), None);
 226
 227     u64_val = u64_val.wrapping_add(1);
 228     assert_eq!(from_str::<u64>("0"), Some(u64_val));
 229     assert_eq!(from_str::<u64>("-1"), None);
 230 }