fix ToTemporalCalendarSlot on to differentiate builtins

core/engine/src/builtins/temporal/calendar/mod.rs

@@ -33,11 +33,6 @@ use boa_temporal::{
 
 mod object;
 
-/*
-#[doc(inline)]
-pub(crate) use object::JsObject;
-*/
-
 #[cfg(test)]
 mod tests;
 /// The `Temporal.Calendar` object.
@@ -1079,7 +1074,12 @@ pub(crate) fn to_temporal_calendar_slot_value(
         }
 
         // c. Return temporalCalendarLike.
-        return Ok(CalendarSlot::Protocol(calendar_like.clone()));
+        match calendar_like.clone().downcast::<Calendar>() {
+            Ok(cal) => return Ok(cal.borrow().data().slot.clone()),
+            Err(custom) => {
+                return Ok(CalendarSlot::Protocol(custom.clone()));
+            }
+        }
     }
 
     // 3. If temporalCalendarLike is not a String, throw a TypeError exception.

core/engine/src/builtins/temporal/plain_date_time/mod.rs

@@ -17,6 +17,9 @@ use crate::{
 use boa_gc::{Finalize, Trace};
 use boa_profiler::Profiler;
 
+#[cfg(test)]
+mod tests;
+
 use boa_temporal::{
     components::{
         calendar::{CalendarSlot, GetCalendarSlot},

core/engine/src/builtins/temporal/plain_date_time/tests.rs

@@ -0,0 +1,10 @@
+use crate::{run_test_actions, TestAction};
+
+#[test]
+fn pdt_year_of_week_basic() {
+    run_test_actions([
+        TestAction::run("let calendar = Temporal.Calendar.from('iso8601')"),
+        TestAction::run("let pdt = new Temporal.PlainDateTime(1976, 11, 18, 15, 23, 30, 123, 456, 789, calendar)"),
+        TestAction::assert_eq("pdt.yearOfWeek", 1976),
+    ]);
+}