1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
extern crate rand;
use rand:: Rng;
use rand::distributions::{Range, IndependentSample};
#[derive(Debug, PartialEq, Eq)]
pub struct Dice {
pub number: u32,
pub sides: u32,
}
impl Dice {
pub fn parse(dice: &str) -> Result<Dice, String> {
let tokens: Vec<&str> = dice.split("d").collect();
if tokens.len() != 2 {
return Err(format!("Invalid dice format '{}'", dice));
}
let number = match tokens[0].parse() {
Ok(num) => num,
Err(_) => return Err(format!("Invalid number of dice '{}'", tokens[0])),
};
let sides = match tokens[1].parse() {
Ok(num) => num,
Err(_) => return Err(format!("Invalid number of sides '{}'", tokens[1])),
};
Ok(Dice { number, sides })
}
pub fn generate<R: Rng>(&self, mut rng: &mut R) -> u32 {
let between = Range::new(1, self.sides);
let mut total = 0;
for _ in 0..self.number {
total += between.ind_sample(&mut rng);
}
total
}
}
#[cfg(test)]
mod test {
use super::*;
use rand::{SeedableRng, StdRng};
#[test]
fn dice_generate() {
let dice = Dice { sides: 6, number: 4 };
let seed: &[_] = &[1, 2, 3, 4];
let mut rng: StdRng = SeedableRng::from_seed(seed);
let result = dice.generate(&mut rng);
assert_eq!(result, 10);
let mut rng = rand::thread_rng();
for _ in 1..100 {
let result = dice.generate(&mut rng);
assert!(result >= 4);
assert!(result <= 24);
}
}
#[test]
fn dice_parse_invalid_number_of_dice() {
assert_eq!(Dice::parse("d6").unwrap_err(), "Invalid number of dice ''");
assert_eq!(Dice::parse("Td10").unwrap_err(), "Invalid number of dice 'T'");
}
#[test]
fn dice_parse_invalid_number_of_sides() {
assert_eq!(Dice::parse("1d").unwrap_err(), "Invalid number of sides ''");
assert_eq!(Dice::parse("1dY").unwrap_err(), "Invalid number of sides 'Y'");
}
#[test]
fn dice_parse_invalid_dice_format() {
assert_eq!(Dice::parse("").unwrap_err(), "Invalid dice format ''");
assert_eq!(Dice::parse("something").unwrap_err(), "Invalid dice format 'something'");
}
#[test]
fn dice_parse_correct() {
assert_eq!(
Dice::parse("6d100"),
Ok(Dice { number: 6, sides: 100 }));
assert_eq!(
Dice::parse("1d5"),
Ok(Dice { number: 1, sides: 5}));
}
}