test: add comprehensive tests for date and Berlin clock conversions

src/__tests__/types.test.ts

@@ -1,10 +0,0 @@
-import { LampState, BerlinClock } from '../types';
-
-describe('Types', () => {
-  it('LampState has correct values', () => {
-    expect(LampState.Y).toBe('Y');
-    expect(LampState.R).toBe('R');
-    expect(LampState.O).toBe('O');
-    expect(LampState.N).toBe('N');
-  });
-});

src/__tests__/utils.test.ts

@@ -1,16 +1,120 @@
 import { dateToDigital, digitalToDate, dateToBerlin, berlinToDate } from '../utils';
+import { LampState } from '../types';
 
 describe('Utils', () => {
-  it('dateToDigital returns correct format', () => {
-    // TODO
+  describe('dateToDigital', () => {
+    it('returns "HH:mm:ss" for a given date', () => {
+      const date = new Date(2025, 0, 1, 14, 5, 9);
+      expect(dateToDigital(date)).toBe('14:05:09');
+    });
+
+    it('pads single-digit hours, minutes, seconds', () => {
+      const date = new Date(2025, 0, 1, 2, 3, 4);
+      expect(dateToDigital(date)).toBe('02:03:04');
+    });
+  });
+
+  describe('digitalToDate', () => {
+    it('parses a valid digital string', () => {
+      const result = digitalToDate('12:34:56');
+      expect(result).toBeInstanceOf(Date);
+      expect(result.getHours()).toBe(12);
+      expect(result.getMinutes()).toBe(34);
+      expect(result.getSeconds()).toBe(56);
+    });
+
+    it('returns an invalid date for invalid input', () => {
+      const result = digitalToDate('abc');
+      expect(isNaN(result.getTime())).toBe(true);
+    });
+  });
+
+  describe('dateToBerlin', () => {
+    const makeTime = (h: number, m: number, s: number) => {
+      const d = new Date(2025, 0, 1, h, m, s);
+      return d;
+    };
+
+    it('returns correct clock for 00:00:00', () => {
+      const clock = dateToBerlin(makeTime(0, 0, 0));
+      expect(clock.secondsRow).toEqual([LampState.Y]);
+      expect(clock.fiveHours).toEqual([LampState.O, LampState.O, LampState.O, LampState.O]);
+      expect(clock.oneHour).toEqual([LampState.O, LampState.O, LampState.O, LampState.O]);
+      expect(clock.fiveMinutes).toEqual([
+        LampState.O, LampState.O, LampState.O,
+        LampState.O, LampState.O, LampState.O,
+        LampState.O, LampState.O, LampState.O,
+        LampState.O, LampState.O,
+      ]);
+      expect(clock.oneMinute).toEqual([LampState.O, LampState.O, LampState.O, LampState.O]);
+    });
+
+    it('returns correct clock for 23:59:59', () => {
+      const clock = dateToBerlin(makeTime(23, 59, 59));
+      expect(clock.secondsRow).toEqual([LampState.O]);
+      expect(clock.fiveHours).toEqual([LampState.R, LampState.R, LampState.R, LampState.R]);
+      expect(clock.oneHour).toEqual([LampState.R, LampState.R, LampState.R, LampState.O]);
+      expect(clock.fiveMinutes).toEqual([
+        LampState.Y, LampState.Y, LampState.R,
+        LampState.Y, LampState.Y, LampState.R,
+        LampState.Y, LampState.Y, LampState.R,
+        LampState.Y, LampState.Y,
+      ]);
+      expect(clock.oneMinute).toEqual([LampState.Y, LampState.Y, LampState.Y, LampState.Y]);
+    });
+
+    it('returns correct clock for 12:34:00', () => {
+      const clock = dateToBerlin(makeTime(12, 34, 0));
+      expect(clock.secondsRow).toEqual([LampState.Y]);
+      expect(clock.fiveHours).toEqual([LampState.R, LampState.R, LampState.O, LampState.O]);
+      expect(clock.oneHour).toEqual([LampState.R, LampState.R, LampState.O, LampState.O]);
+      const expectedFiveMinutes = [
+        LampState.Y, LampState.Y, LampState.R,
+        LampState.Y, LampState.Y, LampState.R,
+        LampState.O, LampState.O, LampState.O,
+        LampState.O, LampState.O,
+      ];
+      expect(clock.fiveMinutes).toEqual(expectedFiveMinutes);
+      expect(clock.oneMinute).toEqual([LampState.Y, LampState.Y, LampState.Y, LampState.Y]);
+    });
+  });
+
+  describe('berlinToDate', () => {
+    it('roundtrips correctly: dateToBerlin then berlinToDate returns the original date (seconds floor to even)', () => {
+      const original = new Date(2025, 0, 1, 14, 30, 0);
+      const clock = dateToBerlin(original);
+      const result = berlinToDate(clock);
+      expect(result.getHours()).toBe(14);
+      expect(result.getMinutes()).toBe(30);
+      expect(result.getSeconds()).toBe(0);
+    });
+
+    it('roundtrips with odd seconds: result seconds will be zero (only parity stored)', () => {
+      const original = new Date(2025, 0, 1, 23, 59, 59);
+      const clock = dateToBerlin(original);
+      const result = berlinToDate(clock);
+      expect(result.getHours()).toBe(23);
+      expect(result.getMinutes()).toBe(59);
+      expect(result.getSeconds()).toBe(0);
+    });
+
+    it('converts a known Berlin clock to the correct time', () => {
+      const clock = {
+        secondsRow: [LampState.Y],
+        fiveHours: [LampState.R, LampState.R, LampState.O, LampState.O],
+        oneHour: [LampState.R, LampState.R, LampState.O, LampState.O],
+        fiveMinutes: [
+          LampState.Y, LampState.Y, LampState.R,
+          LampState.Y, LampState.Y, LampState.R,
+          LampState.Y, LampState.Y, LampState.O,
+          LampState.O, LampState.O,
+        ],
+        oneMinute: [LampState.Y, LampState.Y, LampState.Y, LampState.Y],
+      };
+      const result = berlinToDate(clock);
+      expect(result.getHours()).toBe(12);
+      expect(result.getMinutes()).toBe(34);
+      expect(result.getSeconds()).toBe(0);
     });
-  it('digitalToDate returns a Date', () => {
-    // TODO
-  });
-  it('dateToBerlin returns a BerlinClock', () => {
-    // TODO
-  });
-  it('berlinToDate returns a Date', () => {
-    // TODO
   });
 });