library/core/tests/num/dec2flt/mod.rs

   1 #![allow(overflowing_literals)]
   2
   3 mod parse;
   4 mod rawfp;
   5
   6 // Take a float literal, turn it into a string in various ways (that are all trusted
   7 // to be correct) and see if those strings are parsed back to the value of the literal.
   8 // Requires a *polymorphic literal*, i.e., one that can serve as f64 as well as f32.
   9 macro_rules! test_literal {
  10     ($x: expr) => {{
  11         let x32: f32 = $x;
  12         let x64: f64 = $x;
  13         let inputs = &[stringify!($x).into(), format!("{:?}", x64), format!("{:e}", x64)];
  14         for input in inputs {
  15             assert_eq!(input.parse(), Ok(x64));
  16             assert_eq!(input.parse(), Ok(x32));
  17             let neg_input = &format!("-{}", input);
  18             assert_eq!(neg_input.parse(), Ok(-x64));
  19             assert_eq!(neg_input.parse(), Ok(-x32));
  20         }
  21     }};
  22 }
  23
  24 #[cfg_attr(all(target_arch = "wasm32", target_os = "emscripten"), ignore)] // issue 42630
  25 #[test]
  26 fn ordinary() {
  27     test_literal!(1.0);
  28     test_literal!(3e-5);
  29     test_literal!(0.1);
  30     test_literal!(12345.);
  31     test_literal!(0.9999999);
  32
  33     if cfg!(miri) {
  34         // Miri is too slow
  35         return;
  36     }
  37
  38     test_literal!(2.2250738585072014e-308);
  39 }
  40
  41 #[cfg_attr(all(target_arch = "wasm32", target_os = "emscripten"), ignore)] // issue 42630
  42 #[test]
  43 fn special_code_paths() {
  44     test_literal!(36893488147419103229.0); // 2^65 - 3, triggers half-to-even with even significand
  45     test_literal!(101e-33); // Triggers the tricky underflow case in AlgorithmM (for f32)
  46     test_literal!(1e23); // Triggers AlgorithmR
  47     test_literal!(2075e23); // Triggers another path through AlgorithmR
  48     test_literal!(8713e-23); // ... and yet another.
  49 }
  50
  51 #[test]
  52 fn large() {
  53     test_literal!(1e300);
  54     test_literal!(123456789.34567e250);
  55     test_literal!(943794359898089732078308743689303290943794359843568973207830874368930329.);
  56 }
  57
  58 #[test]
  59 #[cfg_attr(miri, ignore)] // Miri is too slow
  60 fn subnormals() {
  61     test_literal!(5e-324);
  62     test_literal!(91e-324);
  63     test_literal!(1e-322);
  64     test_literal!(13245643e-320);
  65     test_literal!(2.22507385851e-308);
  66     test_literal!(2.1e-308);
  67     test_literal!(4.9406564584124654e-324);
  68 }
  69
  70 #[test]
  71 #[cfg_attr(miri, ignore)] // Miri is too slow
  72 fn infinity() {
  73     test_literal!(1e400);
  74     test_literal!(1e309);
  75     test_literal!(2e308);
  76     test_literal!(1.7976931348624e308);
  77 }
  78
  79 #[test]
  80 fn zero() {
  81     test_literal!(0.0);
  82     test_literal!(1e-325);
  83
  84     if cfg!(miri) {
  85         // Miri is too slow
  86         return;
  87     }
  88
  89     test_literal!(1e-326);
  90     test_literal!(1e-500);
  91 }
  92
  93 #[test]
  94 fn fast_path_correct() {
  95     // This number triggers the fast path and is handled incorrectly when compiling on
  96     // x86 without SSE2 (i.e., using the x87 FPU stack).
  97     test_literal!(1.448997445238699);
  98 }
  99
 100 #[test]
 101 fn lonely_dot() {
 102     assert!(".".parse::<f32>().is_err());
 103     assert!(".".parse::<f64>().is_err());
 104 }
 105
 106 #[test]
 107 fn exponentiated_dot() {
 108     assert!(".e0".parse::<f32>().is_err());
 109     assert!(".e0".parse::<f64>().is_err());
 110 }
 111
 112 #[test]
 113 fn lonely_sign() {
 114     assert!("+".parse::<f32>().is_err());
 115     assert!("-".parse::<f64>().is_err());
 116 }
 117
 118 #[test]
 119 fn whitespace() {
 120     assert!(" 1.0".parse::<f32>().is_err());
 121     assert!("1.0 ".parse::<f64>().is_err());
 122 }
 123
 124 #[test]
 125 fn nan() {
 126     assert!("NaN".parse::<f32>().unwrap().is_nan());
 127     assert!("NaN".parse::<f64>().unwrap().is_nan());
 128 }
 129
 130 #[test]
 131 fn inf() {
 132     assert_eq!("inf".parse(), Ok(f64::INFINITY));
 133     assert_eq!("-inf".parse(), Ok(f64::NEG_INFINITY));
 134     assert_eq!("inf".parse(), Ok(f32::INFINITY));
 135     assert_eq!("-inf".parse(), Ok(f32::NEG_INFINITY));
 136 }
 137
 138 #[test]
 139 fn massive_exponent() {
 140     let max = i64::MAX;
 141     assert_eq!(format!("1e{}000", max).parse(), Ok(f64::INFINITY));
 142     assert_eq!(format!("1e-{}000", max).parse(), Ok(0.0));
 143     assert_eq!(format!("1e{}000", max).parse(), Ok(f64::INFINITY));
 144 }
 145
 146 #[test]
 147 fn borderline_overflow() {
 148     let mut s = "0.".to_string();
 149     for _ in 0..375 {
 150         s.push('3');
 151     }
 152     // At the time of this writing, this returns Err(..), but this is a bug that should be fixed.
 153     // It makes no sense to enshrine that in a test, the important part is that it doesn't panic.
 154     let _ = s.parse::<f64>();
 155 }