tests/f2s_test.rs

// Translated from C to Rust. The original C code can be found at
// https://github.com/ulfjack/ryu and carries the following license:
//
// Copyright 2018 Ulf Adams
//
// The contents of this file may be used under the terms of the Apache License,
// Version 2.0.
//
//    (See accompanying file LICENSE-Apache or copy at
//     http://www.apache.org/licenses/LICENSE-2.0)
//
// Alternatively, the contents of this file may be used under the terms of
// the Boost Software License, Version 1.0.
//    (See accompanying file LICENSE-Boost or copy at
//     https://www.boost.org/LICENSE_1_0.txt)
//
// Unless required by applicable law or agreed to in writing, this software
// is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.

#[macro_use]
mod macros;

use std::f32;

fn pretty(f: f32) -> String {
    ryu::Buffer::new().format(f).to_owned()
}

#[test]
fn test_ryu() {
    check!(0.3);
    check!(1234000000000.0);
    check!(1.234e13);
    check!(2.71828);
    check!(1.1e32);
    check!(1.1e-32);
    check!(2.7182817);
    check!(1e-45);
    check!(3.4028235e38);
    check!(-0.001234);
}

#[test]
fn test_random() {
    let n = if cfg!(miri) { 100 } else { 1000000 };
    let mut buffer = ryu::Buffer::new();
    for _ in 0..n {
        let f: f32 = rand::random();
        assert_eq!(f, buffer.format_finite(f).parse().unwrap());
    }
}

#[test]
#[cfg_attr(miri, ignore)]
fn test_non_finite() {
    for i in 0u32..1 << 23 {
        let f = f32::from_bits((((1 << 8) - 1) << 23) + i);
        assert!(!f.is_finite(), "f={}", f);
        ryu::Buffer::new().format_finite(f);
    }
}

#[test]
fn test_basic() {
    check!(0.0);
    check!(-0.0);
    check!(1.0);
    check!(-1.0);
    assert_eq!(pretty(f32::NAN), "NaN");
    assert_eq!(pretty(f32::INFINITY), "inf");
    assert_eq!(pretty(f32::NEG_INFINITY), "-inf");
}

#[test]
fn test_switch_to_subnormal() {
    check!(1.1754944e-38);
}

#[test]
fn test_min_and_max() {
    assert_eq!(f32::from_bits(0x7f7fffff), 3.4028235e38);
    check!(3.4028235e38);
    assert_eq!(f32::from_bits(1), 1e-45);
    check!(1e-45);
}

// Check that we return the exact boundary if it is the shortest
// representation, but only if the original floating point number is even.
#[test]
fn test_boundary_round_even() {
    check!(33554450.0);
    check!(9000000000.0);
    check!(34366720000.0);
}

// If the exact value is exactly halfway between two shortest representations,
// then we round to even. It seems like this only makes a difference if the
// last two digits are ...2|5 or ...7|5, and we cut off the 5.
#[test]
fn test_exact_value_round_even() {
    check!(305404.12);
    check!(8099.0312);
}

#[test]
fn test_lots_of_trailing_zeros() {
    // Pattern for the first test: 00111001100000000000000000000000
    check!(0.00024414062);
    check!(0.0024414062);
    check!(0.0043945312);
    check!(0.0063476562);
}

#[test]
fn test_regression() {
    check!(4.7223665e21);
    check!(8388608.0);
    check!(16777216.0);
    check!(33554436.0);
    check!(67131496.0);
    check!(1.9310392e-38);
    check!(-2.47e-43);
    check!(1.993244e-38);
    check!(4103.9004);
    check!(5339999700.0);
    check!(6.0898e-39);
    check!(0.0010310042);
    check!(2.882326e17);
    check!(7.038531e-26);
    check!(9.223404e17);
    check!(67108870.0);
    check!(1e-44);
    check!(2.816025e14);
    check!(9.223372e18);
    check!(1.5846086e29);
    check!(1.1811161e19);
    check!(5.368709e18);
    check!(4.6143166e18);
    check!(0.007812537);
    check!(1e-45);
    check!(1.18697725e20);
    check!(1.00014165e-36);
    check!(200.0);
    check!(33554432.0);
}

#[test]
fn test_looks_like_pow5() {
    // These numbers have a mantissa that is the largest power of 5 that fits,
    // and an exponent that causes the computation for q to result in 10, which
    // is a corner case for Ryū.
    assert_eq!(f32::from_bits(0x5D1502F9), 6.7108864e17);
    check!(6.7108864e17);
    assert_eq!(f32::from_bits(0x5D9502F9), 1.3421773e18);
    check!(1.3421773e18);
    assert_eq!(f32::from_bits(0x5E1502F9), 2.6843546e18);
    check!(2.6843546e18);
}

#[test]
fn test_output_length() {
    check!(1.0); // already tested in Basic
    check!(1.2);
    check!(1.23);
    check!(1.234);
    check!(1.2345);
    check!(1.23456);
    check!(1.234567);
    check!(1.2345678);
    check!(1.23456735e-36);
}