Fix first_day implementation

src/date.rs

@@ -525,10 +525,10 @@ where
 
 #[cfg(test)]
 mod tests {
-    use crate::{Datelike, TimeZone, Utc, Weekday, Weeklike};
+    use crate::{Local, Weekday, Weeklike};
 
     #[test]
-    fn test_week_first_day() {
+    fn test_week() {
         let weekdays = [
             Weekday::Mon,
             Weekday::Tue,
@@ -538,10 +538,13 @@ mod tests {
             Weekday::Sat,
             Weekday::Sun,
         ];
-        let date = Utc.ymd(2022, 4, 18);
-        assert_eq!(date.weekday(), Weekday::Mon);
-        for weekday in weekdays {
-            assert!(date.week(weekday).first_day() <= date);
+        let date = Local::today();
+        for start in weekdays {
+            let week = date.week(start);
+            let days = week.days();
+            assert!(week.first_day() <= date);
+            assert!(week.last_day() >= date);
+            assert!(days.contains(&date));
         }
     }
 }

src/naive/date.rs

@@ -19,8 +19,7 @@ use crate::format::{parse, ParseError, ParseResult, Parsed, StrftimeItems};
 use crate::format::{Item, Numeric, Pad};
 use crate::naive::{IsoWeek, NaiveDateTime, NaiveTime};
 use crate::oldtime::Duration as OldDuration;
-use crate::traits::Weeklike;
-use crate::{Datelike, Duration, Weekday};
+use crate::{Datelike, Duration, Weekday, Weeklike};
 
 use super::internals::{self, DateImpl, Mdf, Of, YearFlags};
 use super::isoweek;
@@ -64,10 +63,10 @@ impl Weeklike for NaiveWeek {
 
     #[inline]
     fn first_day(&self) -> Self::Day {
-        let start = self.date.weekday().num_days_from_monday();
-        let end = self.start.num_days_from_monday();
-        let days = if start > end { start - end } else { end - start };
-        self.date - Duration::days(7 - days as i64)
+        let start = self.start.num_days_from_monday();
+        let end = self.date.weekday().num_days_from_monday();
+        let days = if start > end { 7 - end } else { end - start };
+        self.date - Duration::days(days.into())
     }
 }
 
@@ -2441,20 +2440,27 @@ mod tests {
     }
 
     #[test]
-    fn test_naiveweek_first_day() {
-        let weekdays = [
-            Weekday::Mon,
-            Weekday::Tue,
-            Weekday::Wed,
-            Weekday::Thu,
-            Weekday::Fri,
-            Weekday::Sat,
-            Weekday::Sun,
-        ];
-        let date = NaiveDate::from_ymd(2022, 4, 18);
-        assert_eq!(date.weekday(), Weekday::Mon);
-        for start in weekdays {
-            assert!(date.week(start).first_day() <= date);
-        }
+    fn test_naiveweek_less_than_weekday() {
+        let date = NaiveDate::from_ymd(2022, 5, 18);
+        let week = date.week(Weekday::Mon);
+        assert_eq!(week.first_day(), NaiveDate::from_ymd(2022, 5, 16));
+        assert_eq!(week.last_day(), NaiveDate::from_ymd(2022, 5, 22));
+    }
+
+    #[test]
+    fn test_naiveweek_equal_to_weekday() {
+        let date = NaiveDate::from_ymd(2022, 5, 18);
+        let week = date.week(Weekday::Wed);
+        assert_eq!(week.first_day(), date);
+        assert_eq!(week.last_day(), NaiveDate::from_ymd(2022, 5, 24));
+    }
+
+    /// TODO: Fix this test
+    #[test]
+    fn test_naiveweek_greater_than_weekday() {
+        let date = NaiveDate::from_ymd(2022, 5, 18);
+        let week = date.week(Weekday::Fri);
+        assert_eq!(week.first_day(), NaiveDate::from_ymd(2022, 5, 13));
+        assert_eq!(week.last_day(), NaiveDate::from_ymd(2022, 5, 19));
     }
 }

src/traits.rs

@@ -313,20 +313,20 @@ mod tests {
 
     #[test]
     fn test_weeklike_last_day() {
-        let first_day = NaiveDate::from_ymd(2022, 4, 18);
-        let week = FakeWeek { date: first_day };
+        let date = NaiveDate::from_ymd(2022, 4, 18);
+        let week = FakeWeek { date };
         let last_day = week.last_day();
-        assert_eq!(first_day.weekday(), Weekday::Mon);
+        assert_eq!(date.weekday(), Weekday::Mon);
         assert_eq!(last_day.weekday(), Weekday::Sun);
         assert_eq!(last_day, NaiveDate::from_ymd(2022, 4, 24));
     }
 
     #[test]
     fn test_weeklike_days() {
-        let first_day = NaiveDate::from_ymd(2022, 4, 18);
-        let week = FakeWeek { date: first_day };
+        let date = NaiveDate::from_ymd(2022, 4, 18);
+        let week = FakeWeek { date };
         let days = week.days();
-        assert_eq!(days.start(), &first_day);
+        assert_eq!(days.start(), &week.first_day());
         assert_eq!(days.end(), &week.last_day());
     }
 }