Fix availability of december background (#15378)

test/content/schedule.test.js

@@ -272,6 +272,21 @@ describe('Content Schedule', () => {
       expect(matcher.match('backgroundkey072024')).to.be.true;
     });
 
+    it('allows background matching the month for new backgrounds from multiple years', () => {
+      const date = new Date('2026-07-08');
+      const matcher = getAllScheduleMatchingGroups(date).backgrounds;
+      expect(matcher.match('backgroundkey072024')).to.be.true;
+      expect(matcher.match('backgroundkey072025')).to.be.true;
+      expect(matcher.match('backgroundkey072026')).to.be.true;
+    });
+
+    it('allows background matching the previous month in the first week for new backgrounds', () => {
+      const date = new Date('2024-09-02');
+      const matcher = getAllScheduleMatchingGroups(date).backgrounds;
+      expect(matcher.match('backgroundkey082024')).to.be.true;
+      expect(matcher.match('backgroundkey092024')).to.be.false;
+    });
+
     it('disallows background in the future', () => {
       const date = new Date('2024-07-08');
       const matcher = getAllScheduleMatchingGroups(date).backgrounds;
@@ -291,19 +306,26 @@ describe('Content Schedule', () => {
       expect(matcher.match('backgroundkey022021')).to.be.true;
     });
 
-    it('allows background even yeared backgrounds in first half of year', () => {
+    it('allows even yeared backgrounds in first half of year', () => {
       const date = new Date('2025-02-08');
       const matcher = getAllScheduleMatchingGroups(date).backgrounds;
       expect(matcher.match('backgroundkey022024')).to.be.true;
       expect(matcher.match('backgroundkey082022')).to.be.true;
     });
 
-    it('allows background odd yeared backgrounds in second half of year', () => {
+    it('allows odd yeared backgrounds in second half of year', () => {
       const date = new Date('2024-08-08');
       const matcher = getAllScheduleMatchingGroups(date).backgrounds;
       expect(matcher.match('backgroundkey022023')).to.be.true;
       expect(matcher.match('backgroundkey082021')).to.be.true;
     });
+
+    it('allows odd yeared backgrounds in beginning of january', () => {
+      const date = new Date('2025-01-06');
+      const matcher = getAllScheduleMatchingGroups(date).backgrounds;
+      expect(matcher.match('backgroundkey122024'), 'backgroundkey122024').to.be.true;
+      expect(matcher.match('backgroundkey062023'), 'backgroundkey062022').to.be.true;
+    });
   });
 
   describe('timeTravelers matcher', () => {

website/common/script/content/constants/schedule.js

@@ -18,7 +18,10 @@ function backgroundMatcher (month1, month2, oddYear) {
     const month = parseInt(key.substring(keyLength - 6, keyLength - 4), 10);
     const year = parseInt(key.substring(keyLength - 4, keyLength), 10);
     if (isAfterNewSchedule(year, month)) {
-      return month === month1 && date.getFullYear() >= year && (date.getMonth() + 1) >= month;
+      if (date.getMonth() === 0 && month1 === 12) {
+        return month === month1 && (date.getFullYear() - 1) >= year;
+      }
+      return month === month1 && date.getFullYear() >= year;
     }
     return (month === month1 || month === month2) && year % 2 === (oddYear ? 1 : 0);
   };