fix(domain): improve Weekday tests and document all() ordering

k-tv-backend/domain/src/value_objects/scheduling.rs

@@ -168,6 +168,8 @@ impl From<chrono::Weekday> for Weekday {
 
 impl Weekday {
     pub fn all() -> [Weekday; 7] {
+        // ISO week order: Monday = index 0, Sunday = index 6.
+        // The schedule engine depends on this order when iterating days.
         [
             Weekday::Monday, Weekday::Tuesday, Weekday::Wednesday,
             Weekday::Thursday, Weekday::Friday, Weekday::Saturday, Weekday::Sunday,
@@ -180,13 +182,20 @@ mod weekday_tests {
     use super::*;
 
     #[test]
-    fn from_chrono_weekday_roundtrip() {
+    fn from_chrono_weekday_all_variants() {
         assert_eq!(Weekday::from(chrono::Weekday::Mon), Weekday::Monday);
+        assert_eq!(Weekday::from(chrono::Weekday::Tue), Weekday::Tuesday);
+        assert_eq!(Weekday::from(chrono::Weekday::Wed), Weekday::Wednesday);
+        assert_eq!(Weekday::from(chrono::Weekday::Thu), Weekday::Thursday);
+        assert_eq!(Weekday::from(chrono::Weekday::Fri), Weekday::Friday);
+        assert_eq!(Weekday::from(chrono::Weekday::Sat), Weekday::Saturday);
         assert_eq!(Weekday::from(chrono::Weekday::Sun), Weekday::Sunday);
     }
 
     #[test]
-    fn all_has_seven_days() {
-        assert_eq!(Weekday::all().len(), 7);
+    fn all_returns_monday_first_sunday_last() {
+        let days = Weekday::all();
+        assert_eq!(days[0], Weekday::Monday);
+        assert_eq!(days[6], Weekday::Sunday);
     }
 }