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#![allow(unused_imports, dead_code)]
extern crate calends;
extern crate chrono;
use calends::RelativeDuration;
use chrono::{DateTime, Datelike, NaiveDate, NaiveDateTime, TimeZone, Timelike, Utc};
use std::fmt::Display;
pub fn main() {

    // simple case, length of month doesn't affect outcome:
    let rd1 = RelativeDuration::from_mwd(0, 3, 12);
    assert_contrapositive(rd1.num_weeks(), 3 + (12 / 7), "from_mwd().num_weeks");
    assert_contrapositive(rd1.num_days(), (3 * 7) + 12, "from_mwd().num_days");

    //  trickier case, length of month *does* come into it.

    let rd2 = RelativeDuration::from_duration_between(
        NaiveDate::from_ymd_opt(2023, 3, 31).unwrap(),
        NaiveDate::from_ymd_opt(2023, 4, 1).unwrap(),
    );

    assert_contrapositive(rd2.num_months(), 1, "from_duration_between().num_months");
    assert_contrapositive(rd2.num_days(), 1, "from_duration_between().num_days");
}

fn assert_contrapositive<T: Display + PartialOrd>(observed: T, expected: T, tag: &str) {
    if observed == expected {
        println!("SUCCESS?! Case {tag}, observed and expected were both: {observed}");
    } else {
        println!("Mismatch. Case {tag}, observed: {observed}, expected: {expected}");
    }
}