diff --git a/test/common/datetime/check_time.test.ts b/test/common/datetime/check_time.test.ts
new file mode 100644
index 0000000000..7a33dd126f
--- /dev/null
+++ b/test/common/datetime/check_time.test.ts
@@ -0,0 +1,164 @@
+import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
+import { checkTimeInRange } from "../../../src/common/datetime/check_time";
+import type { HomeAssistant } from "../../../src/types";
+import {
+  NumberFormat,
+  TimeFormat,
+  FirstWeekday,
+  DateFormat,
+  TimeZone,
+} from "../../../src/data/translation";
+
+describe("checkTimeInRange", () => {
+  let mockHass: HomeAssistant;
+
+  beforeEach(() => {
+    mockHass = {
+      locale: {
+        language: "en-US",
+        number_format: NumberFormat.language,
+        time_format: TimeFormat.language,
+        date_format: DateFormat.language,
+        time_zone: TimeZone.local,
+        first_weekday: FirstWeekday.language,
+      },
+      config: {
+        time_zone: "America/Los_Angeles",
+      },
+    } as HomeAssistant;
+  });
+
+  afterEach(() => {
+    vi.useRealTimers();
+  });
+
+  describe("time ranges within same day", () => {
+    it("should return true when current time is within range", () => {
+      // Set time to 10:00 AM
+      vi.setSystemTime(new Date(2024, 0, 15, 10, 0, 0));
+
+      expect(checkTimeInRange(mockHass, "08:00", "17:00")).toBe(true);
+    });
+
+    it("should return false when current time is before range", () => {
+      // Set time to 7:00 AM
+      vi.setSystemTime(new Date(2024, 0, 15, 7, 0, 0));
+
+      expect(checkTimeInRange(mockHass, "08:00", "17:00")).toBe(false);
+    });
+
+    it("should return false when current time is after range", () => {
+      // Set time to 6:00 PM
+      vi.setSystemTime(new Date(2024, 0, 15, 18, 0, 0));
+
+      expect(checkTimeInRange(mockHass, "08:00", "17:00")).toBe(false);
+    });
+  });
+
+  describe("time ranges crossing midnight", () => {
+    it("should return true when current time is before midnight", () => {
+      // Set time to 11:00 PM
+      vi.setSystemTime(new Date(2024, 0, 15, 23, 0, 0));
+
+      expect(checkTimeInRange(mockHass, "22:00", "06:00")).toBe(true);
+    });
+
+    it("should return true when current time is after midnight", () => {
+      // Set time to 3:00 AM
+      vi.setSystemTime(new Date(2024, 0, 15, 3, 0, 0));
+
+      expect(checkTimeInRange(mockHass, "22:00", "06:00")).toBe(true);
+    });
+
+    it("should return false when outside the range", () => {
+      // Set time to 10:00 AM
+      vi.setSystemTime(new Date(2024, 0, 15, 10, 0, 0));
+
+      expect(checkTimeInRange(mockHass, "22:00", "06:00")).toBe(false);
+    });
+  });
+
+  describe("only 'after' condition", () => {
+    it("should return true when after specified time", () => {
+      vi.setSystemTime(new Date(2024, 0, 15, 10, 0, 0));
+      expect(checkTimeInRange(mockHass, "08:00")).toBe(true);
+    });
+
+    it("should return false when before specified time", () => {
+      vi.setSystemTime(new Date(2024, 0, 15, 6, 0, 0));
+      expect(checkTimeInRange(mockHass, "08:00")).toBe(false);
+    });
+  });
+
+  describe("only 'before' condition", () => {
+    it("should return true when before specified time", () => {
+      vi.setSystemTime(new Date(2024, 0, 15, 10, 0, 0));
+      expect(checkTimeInRange(mockHass, undefined, "17:00")).toBe(true);
+    });
+
+    it("should return false when after specified time", () => {
+      vi.setSystemTime(new Date(2024, 0, 15, 18, 0, 0));
+      expect(checkTimeInRange(mockHass, undefined, "17:00")).toBe(false);
+    });
+  });
+
+  describe("weekday filtering", () => {
+    it("should return true on matching weekday", () => {
+      // January 15, 2024 is a Monday
+      vi.setSystemTime(new Date(2024, 0, 15, 10, 0, 0));
+
+      expect(checkTimeInRange(mockHass, undefined, undefined, ["mon"])).toBe(
+        true
+      );
+    });
+
+    it("should return false on non-matching weekday", () => {
+      // January 15, 2024 is a Monday
+      vi.setSystemTime(new Date(2024, 0, 15, 10, 0, 0));
+
+      expect(checkTimeInRange(mockHass, undefined, undefined, ["tue"])).toBe(
+        false
+      );
+    });
+
+    it("should work with multiple weekdays", () => {
+      // January 15, 2024 is a Monday
+      vi.setSystemTime(new Date(2024, 0, 15, 10, 0, 0));
+
+      expect(
+        checkTimeInRange(mockHass, undefined, undefined, ["mon", "wed", "fri"])
+      ).toBe(true);
+    });
+  });
+
+  describe("combined time and weekday conditions", () => {
+    it("should return true when both match", () => {
+      // January 15, 2024 is a Monday at 10:00 AM
+      vi.setSystemTime(new Date(2024, 0, 15, 10, 0, 0));
+
+      expect(checkTimeInRange(mockHass, "08:00", "17:00", ["mon"])).toBe(true);
+    });
+
+    it("should return false when time matches but weekday doesn't", () => {
+      // January 15, 2024 is a Monday at 10:00 AM
+      vi.setSystemTime(new Date(2024, 0, 15, 10, 0, 0));
+
+      expect(checkTimeInRange(mockHass, "08:00", "17:00", ["tue"])).toBe(false);
+    });
+
+    it("should return false when weekday matches but time doesn't", () => {
+      // January 15, 2024 is a Monday at 6:00 AM
+      vi.setSystemTime(new Date(2024, 0, 15, 6, 0, 0));
+
+      expect(checkTimeInRange(mockHass, "08:00", "17:00", ["mon"])).toBe(false);
+    });
+  });
+
+  describe("no conditions", () => {
+    it("should return true when no conditions specified", () => {
+      vi.setSystemTime(new Date(2024, 0, 15, 10, 0, 0));
+
+      expect(checkTimeInRange(mockHass)).toBe(true);
+    });
+  });
+});