Add tests for DST transitions

Author: timmo001

test/common/datetime/check_time.test.ts

@@ -161,4 +161,49 @@ describe("checkTimeInRange", () => {
       expect(checkTimeInRange(mockHass)).toBe(true);
     });
   });
+
+  describe("DST transitions", () => {
+    it("should handle spring forward transition (losing an hour)", () => {
+      // March 10, 2024 at 1:30 AM PST - before spring forward
+      // At 2:00 AM, clocks jump to 3:00 AM PDT
+      vi.setSystemTime(new Date(2024, 2, 10, 1, 30, 0));
+
+      // Should be within range that crosses the transition
+      expect(checkTimeInRange(mockHass, "01:00", "04:00")).toBe(true);
+    });
+
+    it("should handle spring forward transition after the jump", () => {
+      // March 10, 2024 at 3:30 AM PDT - after spring forward
+      vi.setSystemTime(new Date(2024, 2, 10, 3, 30, 0));
+
+      // Should still be within range
+      expect(checkTimeInRange(mockHass, "01:00", "04:00")).toBe(true);
+    });
+
+    it("should handle fall back transition (gaining an hour)", () => {
+      // November 3, 2024 at 1:30 AM PDT - before fall back
+      // At 2:00 AM PDT, clocks fall back to 1:00 AM PST
+      vi.setSystemTime(new Date(2024, 10, 3, 1, 30, 0));
+
+      // Should be within range that crosses the transition
+      expect(checkTimeInRange(mockHass, "01:00", "03:00")).toBe(true);
+    });
+
+    it("should handle midnight crossing during DST transition", () => {
+      // March 10, 2024 at 1:00 AM - during spring forward night
+      vi.setSystemTime(new Date(2024, 2, 10, 1, 0, 0));
+
+      // Range that crosses midnight and DST transition
+      expect(checkTimeInRange(mockHass, "22:00", "04:00")).toBe(true);
+    });
+
+    it("should correctly compare times on DST transition day", () => {
+      // November 3, 2024 at 10:00 AM - after fall back completed
+      vi.setSystemTime(new Date(2024, 10, 3, 10, 0, 0));
+
+      // Normal business hours should work correctly
+      expect(checkTimeInRange(mockHass, "08:00", "17:00")).toBe(true);
+      expect(checkTimeInRange(mockHass, "12:00", "17:00")).toBe(false);
+    });
+  });
 });