Add tests

Author: martijnrusschen

src/test/timezone_test.test.tsx

@@ -0,0 +1,133 @@
+import {
+  toZonedTime,
+  fromZonedTime,
+  formatInTimeZone,
+  nowInTimeZone,
+} from "../date_utils";
+
+describe("Timezone utility functions", () => {
+  const testDate = new Date("2024-06-15T12:00:00Z");
+
+  describe("toZonedTime", () => {
+    it("should return the original date when no timezone is provided", () => {
+      const result = toZonedTime(testDate);
+      expect(result).toBe(testDate);
+    });
+
+    it("should return the original date when timezone is undefined", () => {
+      const result = toZonedTime(testDate, undefined);
+      expect(result).toBe(testDate);
+    });
+
+    it("should return the original date when date-fns-tz is not installed", () => {
+      // Suppress console.warn for this test
+      const warnSpy = jest.spyOn(console, "warn").mockImplementation(() => {});
+
+      // Since date-fns-tz is not installed, it should return the original date
+      const result = toZonedTime(testDate, "America/New_York");
+      expect(result).toBe(testDate);
+
+      // Should have warned about missing date-fns-tz
+      expect(warnSpy).toHaveBeenCalledWith(
+        expect.stringContaining("date-fns-tz"),
+      );
+
+      warnSpy.mockRestore();
+    });
+  });
+
+  describe("fromZonedTime", () => {
+    it("should return the original date when no timezone is provided", () => {
+      const result = fromZonedTime(testDate);
+      expect(result).toBe(testDate);
+    });
+
+    it("should return the original date when timezone is undefined", () => {
+      const result = fromZonedTime(testDate, undefined);
+      expect(result).toBe(testDate);
+    });
+
+    it("should return the original date when date-fns-tz is not installed", () => {
+      // Suppress console.warn for this test
+      const warnSpy = jest.spyOn(console, "warn").mockImplementation(() => {});
+
+      // Since date-fns-tz is not installed, it should return the original date
+      const result = fromZonedTime(testDate, "America/New_York");
+      expect(result).toBe(testDate);
+
+      warnSpy.mockRestore();
+    });
+  });
+
+  describe("formatInTimeZone", () => {
+    it("should use standard format when no timezone is provided", () => {
+      const result = formatInTimeZone(testDate, "yyyy-MM-dd");
+      // Without timezone, it should use the standard format function
+      expect(result).toBe("2024-06-15");
+    });
+
+    it("should use standard format when date-fns-tz is not installed", () => {
+      // Suppress console.warn for this test
+      const warnSpy = jest.spyOn(console, "warn").mockImplementation(() => {});
+
+      // Since date-fns-tz is not installed, it should fall back to standard format
+      const result = formatInTimeZone(
+        testDate,
+        "yyyy-MM-dd",
+        "America/New_York",
+      );
+      expect(result).toBe("2024-06-15");
+
+      warnSpy.mockRestore();
+    });
+  });
+
+  describe("nowInTimeZone", () => {
+    it("should return current date when no timezone is provided", () => {
+      const before = new Date();
+      const result = nowInTimeZone();
+      const after = new Date();
+
+      expect(result.getTime()).toBeGreaterThanOrEqual(before.getTime());
+      expect(result.getTime()).toBeLessThanOrEqual(after.getTime());
+    });
+
+    it("should return current date when date-fns-tz is not installed", () => {
+      // Suppress console.warn for this test
+      const warnSpy = jest.spyOn(console, "warn").mockImplementation(() => {});
+
+      const before = new Date();
+      const result = nowInTimeZone("America/New_York");
+      const after = new Date();
+
+      // The result should be a Date object within the expected range
+      expect(result).toBeInstanceOf(Date);
+      expect(result.getTime()).toBeGreaterThanOrEqual(before.getTime());
+      expect(result.getTime()).toBeLessThanOrEqual(after.getTime());
+
+      warnSpy.mockRestore();
+    });
+  });
+});
+
+describe("Timezone utility functions - edge cases", () => {
+  it("should handle empty string timezone", () => {
+    const testDate = new Date("2024-06-15T12:00:00Z");
+    const result = toZonedTime(testDate, "");
+    // Empty string is falsy, so should return original date
+    expect(result).toBe(testDate);
+  });
+
+  it("should handle various date inputs", () => {
+    const dates = [
+      new Date("2024-01-01T00:00:00Z"),
+      new Date("2024-06-15T12:30:45Z"),
+      new Date("2024-12-31T23:59:59Z"),
+    ];
+
+    dates.forEach((date) => {
+      const result = toZonedTime(date);
+      expect(result).toBe(date);
+    });
+  });
+});