Created
June 1, 2018 12:51
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Proptest
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#[cfg(test)] | |
#[macro_use] | |
extern crate proptest; | |
extern crate chrono; | |
use chrono::prelude::*; | |
use std::convert::From; | |
use std::num::ParseIntError; | |
#[derive(Debug, PartialEq)] | |
pub enum Error { | |
Parse, | |
InvalidDate, | |
} | |
impl From<ParseIntError> for Error { | |
fn from(_e: ParseIntError) -> Error { | |
Error::Parse | |
} | |
} | |
fn match_month(month: impl AsRef<str>) -> u32 { | |
match month.as_ref() { | |
"January" => 1, | |
"February" => 2, | |
"March" => 3, | |
"April" => 4, | |
"May" => 5, | |
"June" => 6, | |
"July" => 7, | |
"August" => 8, | |
"September" => 9, | |
"October" => 10, | |
"November" => 11, | |
"December" => 12, | |
_ => unreachable!(), | |
} | |
} | |
pub fn parse(humandate: impl AsRef<str>) -> Result<chrono::NaiveDate, Error> { | |
let parts: Vec<String> = humandate | |
.as_ref() | |
.split_whitespace() | |
.map(String::from) | |
.collect(); | |
if parts.len() != 4 { | |
return Err(Error::Parse); | |
} | |
let day_human = &parts[0]; | |
let month_human = &parts[2]; | |
let year = parts[3].parse::<i32>()?; | |
let (day_str, _suffix) = day_human.split_at(2); | |
let day = day_str.parse::<u32>()?; | |
let month = match_month(month_human); | |
// Avoid chrono panic: 'No such local time' | |
// see chrono/src/offset/mod.rs:145:34 | |
NaiveDate::from_ymd_opt(year, month, day).ok_or(Error::InvalidDate) | |
} | |
#[cfg(test)] | |
mod test { | |
use super::*; | |
#[test] | |
fn test_valid() { | |
assert_eq!( | |
parse("15th of May 2015"), | |
Ok(NaiveDate::from_ymd(2015, 5, 15)) | |
); | |
} | |
#[test] | |
fn test_invalid() { | |
assert_eq!(parse("50th of May 2015"), Err(Error::InvalidDate)); | |
} | |
proptest! { | |
#[test] | |
fn doesnt_crash(ref s in "\\PC*") { | |
parse(s); | |
} | |
#[test] | |
fn parses_all_valid_dates(ref s in "([0-2](1st|2nd|3rd|[4-9]th)|10th|20th|30th|31st) of (January) -?(0|[1-9][0-9]{4})") { | |
parse(s).unwrap(); | |
} | |
#[test] | |
fn parses_date_back_to_original(y in 0i32..10000, | |
m in 1u32..13, d in 1u32..32) { | |
println!("y = {}, m = {}, d = {}", y, m, d); | |
let month = match m { | |
1 => "January", | |
2 => "February", | |
3 => "March", | |
4 => "April", | |
5 => "May", | |
6 => "June", | |
7 => "July", | |
8 => "August", | |
9 => "September", | |
10 => "October", | |
11 => "November", | |
12 => "December", | |
_ => unreachable!(), | |
}; | |
let suffix = match d { | |
1 => "st", | |
2 => "nd", | |
3 => "rd", | |
_ => "th", | |
}; | |
let date = parse(&format!("{:02}{} of {} {:02}", d, suffix, month, y)); | |
prop_assert_eq!(NaiveDate::from_ymd_opt(y, m, d).ok_or(Error::InvalidDate), date); | |
} | |
} | |
} |
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