[chronotope#654] Get week start and end days

src/naive/isoweek.rs

@@ -4,6 +4,11 @@
 //! ISO 8601 week.
 
 use core::fmt;
+use std::ops::Range;
+
+use time::Duration;
+
+use crate::{Weekday, NaiveDate};
 
 use super::internals::{DateImpl, Of, YearFlags};
 
@@ -104,6 +109,21 @@ impl IsoWeek {
     pub fn week0(&self) -> u32 {
         ((self.ywf >> 4) & 0x3f) as u32 - 1
     }
+
+    /// TODO: missing docs
+    pub fn start_day(&self, weekday: Weekday) -> NaiveDate {
+        NaiveDate::from_isoywd(self.year(), self.week(), weekday)
+    }
+
+    /// TODO: missing docs
+    pub fn end_day(&self, weekday: Weekday) -> NaiveDate {
+        self.start_day(weekday) + Duration::days(6)
+    }
+
+    /// TODO: missing docs
+    pub fn bounds(&self, weekday: Weekday) -> Range<NaiveDate> {
+        self.start_day(weekday)..self.end_day(weekday)
+    }
 }
 
 /// The `Debug` output of the ISO week `w` is the same as
@@ -143,7 +163,7 @@ impl fmt::Debug for IsoWeek {
 #[cfg(test)]
 mod tests {
     use crate::naive::{internals, MAX_DATE, MIN_DATE};
-    use crate::Datelike;
+    use crate::{Datelike, NaiveDate, Weekday};
 
     #[test]
     fn test_iso_week_extremes() {
@@ -160,4 +180,29 @@ mod tests {
         assert_eq!(maxweek.week0(), 0);
         assert_eq!(format!("{:?}", maxweek), MAX_DATE.format("%G-W%V").to_string());
     }
+
+    #[test]
+    fn test_start_day() {
+        let week = NaiveDate::from_ymd(2022, 3, 28).iso_week();
+
+        assert_eq!(week.start_day(Weekday::Mon), NaiveDate::from_ymd(2022, 3, 28));
+        assert_eq!(week.start_day(Weekday::Tue), NaiveDate::from_ymd(2022, 3, 29));
+    }
+
+    #[test]
+    fn test_end_day() {
+        let week = NaiveDate::from_ymd(2022, 3, 28).iso_week();
+
+        assert_eq!(week.end_day(Weekday::Mon), NaiveDate::from_ymd(2022, 4, 3));
+        assert_eq!(week.end_day(Weekday::Tue), NaiveDate::from_ymd(2022, 4, 4));
+    }
+
+    #[test]
+    fn test_bounds() {
+        let date = NaiveDate::from_ymd(2022, 3, 28);
+        let week = date.iso_week();
+
+        assert!(week.bounds(Weekday::Mon).contains(&date));
+        assert!(week.bounds(Weekday::Tue).contains(&date));
+    }
 }