North West | 26-ITP-Sep | Brian Yorachi | Sprint 1 | Exhaustively test and fix formatAs12HourClock

format-clock-edge-cases/timeConverter.js

@@ -1,10 +1,24 @@
 function formatAs12HourClock(time) {
+  if (typeof time !== "string") {
+    throw new TypeError("time must be a string in HH:mm format");
+  }
 
   const hours = Number(time.slice(0, 2));
+  const minutes = time.slice(3);
+
+  if (hours === 0) {
+    return `12:${minutes} am`;
+  }
 
   if (hours > 12) {
-    return `${hours - 12}:00 pm`;
+    const pmHours = String(hours - 12).padStart(2, "0");
+    return `${pmHours}:${minutes} pm`;
   }
+
+  if (hours === 12) {
+    return `${time} pm`;
+  }
+
   return `${time} am`;
 }
 

format-clock-edge-cases/timeConverter.test.js

@@ -1,11 +1,43 @@
-import {formatAs12HourClock} from "./timeConverter.js";
-import assert from "node:assert";
+import { formatAs12HourClock } from "./timeConverter.js";
+import assert from "node:assert/strict";
 import test from "node:test";
 
-test("correctly convert time after 12:00", function(){
-    assert.equal(formatAs12HourClock("23:00"), "11:00 pm");
-});
+const cases = [
+    ["00:00", "12:00 am"],
+    ["00:01", "12:01 am"],
+    ["01:05", "01:05 am"],
+    ["08:00", "08:00 am"],
+    ["11:59", "11:59 am"],
+    ["12:00", "12:00 pm"],
+    ["12:34", "12:34 pm"],
+    ["13:00", "01:00 pm"],
+    ["13:30", "01:30 pm"],
+    ["15:45", "03:45 pm"],
+    ["23:00", "11:00 pm"],
+    ["23:59", "11:59 pm"],
+];
+
+for (const [time, expected] of cases) {
+    test(`${time} converts to ${expected}`, () => {
+        assert.equal(formatAs12HourClock(time), expected);
+    });
+}
+
+for (const value of [true, false, [], ["08:00"], {}, 800, null, undefined]) {
+    test(`throws a TypeError for non-string input ${JSON.stringify(value)}`, () => {
+        assert.throws(() => formatAs12HourClock(value), TypeError);
+    });
+}
+
+test("converts every valid minute of the day", () => {
+    for (let hour = 0; hour < 24; hour += 1) {
+        for (let minute = 0; minute < 60; minute += 1) {
+            const time = `${String(hour).padStart(2, "0")}:${String(minute).padStart(2, "0")}`;
+            const convertedHour = hour % 12 || 12;
+            const period = hour < 12 ? "am" : "pm";
+            const expected = `${String(convertedHour).padStart(2, "0")}:${String(minute).padStart(2, "0")} ${period}`;
 
-test("can correctly convert morning time", function() {
-    assert.equal(formatAs12HourClock("08:00"), "08:00 am");
+            assert.equal(formatAs12HourClock(time), expected, time);
+        }
+    }
 });