finance_solution/
round.rs

1//! **Utilities for rounding** money amounts to the nearest hundredth or ten-thousandth part.
2
3/// Round to two decimal places. This function uses f64::round() which rounds halfway cases away
4/// from 0.0.
5pub fn round_2(val: f64) -> f64 {
6    (val * 100.0).round() / 100.0
7}
8
9/// Round to four decimal places. This function uses f64::round() which rounds halfway cases away
10/// from 0.0.
11pub fn round_4(val: f64) -> f64 {
12    (val * 10_000.0).round() / 10_000.0
13}
14
15/// Round to six decimal places. This function uses f64::round() which rounds halfway cases away
16/// from 0.0.
17pub fn round_6(val: f64) -> f64 {
18    (val * 1_000_000.0).round() / 1_000_000.0
19}
20
21/// Round to eight decimal places. This function uses f64::round() which rounds halfway cases away
22/// from 0.0.
23pub fn round_8(val: f64) -> f64 {
24    (val * 100_000_000.0).round() / 100_000_000.0
25}
26
27#[inline(always)]
28pub fn assert_rounded_2(val_1: f64, val_2: f64) {
29    assert!(val_1.is_finite());
30    assert!(val_2.is_finite());
31    assert_eq!(round_2(val_1), round_2(val_2));
32}
33
34#[inline(always)]
35pub fn assert_rounded_4(val_1: f64, val_2: f64) {
36    assert!(val_1.is_finite());
37    assert!(val_2.is_finite());
38    assert_eq!(round_4(val_1), round_4(val_2));
39}
40
41#[inline(always)]
42pub fn assert_rounded_6(val_1: f64, val_2: f64) {
43    assert!(val_1.is_finite());
44    assert!(val_2.is_finite());
45    assert_eq!(round_6(val_1), round_6(val_2));
46}
47
48#[inline(always)]
49pub fn assert_rounded_8(val_1: f64, val_2: f64) {
50    assert!(val_1.is_finite());
51    assert!(val_2.is_finite());
52    assert_eq!(round_8(val_1), round_8(val_2));
53}
54
55#[cfg(test)]
56mod tests {
57    use super::*;
58    use crate::*;
59
60    #[test]
61    fn test_equals_zero() {
62        assert_eq!(0.0f64, 0.0f64);
63        assert_eq!(-0.0f64, -0.0f64);
64        assert_eq!(0.0f64, -0.0f64);
65    }
66
67    #[test]
68    fn test_round_2() {
69        assert_eq!(295_489.94, round_2(295_489.941849));
70        assert_eq!(295_489.94, round_2(295_489.9449));
71        assert_ne!(295_489.94, round_2(295_489.9451234));
72    }
73
74    #[test]
75    fn test_round_4() {
76        assert_eq!(295_489.9418, round_4(295_489.941849));
77        assert_eq!(295_489.9418, round_4(295_489.94175));
78        assert_ne!(295_489.9418, round_4(295_489.94185));
79    }
80
81    #[test]
82    fn test_round_6() {
83        assert_eq!(295_489.941849, round_6(295_489.9418494449));
84        assert_eq!(295_489.533367, round_6(295_489.5333669999999));
85        assert_eq!(295_489.945123, round_6(295_489.9451229999));
86        assert_ne!(295_489.945123, round_6(295_489.9451249999));
87    }
88
89    #[test]
90    fn test_round_8() {
91        assert_eq!(295_489.94184944, round_8(295_489.9418494449));
92        assert_eq!(295_489.53336700, round_8(295_489.5333669999999));
93        assert_eq!(295_489.94512333, round_8(295_489.945123329999));
94        assert_ne!(295_489.94512333, round_8(295_489.9451249999));
95    }
96
97    #[test]
98    fn test_assert_rounded_2_nominal() {
99        assert_rounded_2!(53_243.7448, 53_243.7401);
100    }
101
102    #[test]
103    #[should_panic]
104    fn test_assert_rounded_2_panic() {
105        assert_rounded_2!(53_243.7458, 53_243.7401);
106    }
107
108    /*
109    #[test]
110    fn test_assert_approx_equal() {
111        assert_approx_equal!(53_243.7448, 53_243.7401);
112    }
113    */
114
115    #[test]
116    #[should_panic]
117    fn test_assert_approx_equal_panic() {
118        assert_rounded_2!(53_243.8123, 53_243.7401);
119    }
120
121}
122
123
finance_solution/round.rs

finance_solution/
round.rs
