diff --git a/duration.test.mjs b/duration.test.mjs
index 7183f9d..ab9ca65 100644
--- a/duration.test.mjs
+++ b/duration.test.mjs
@@ -5,3 +5,79 @@ import { parseDuration } from './duration.mjs';
 test('converts a normal work duration to minutes', () => {
   assert.equal(parseDuration('1:30'), 90);
 });
+
+test('converts other normal durations to minutes', () => {
+  assert.equal(parseDuration('0:45'), 45);
+  assert.equal(parseDuration('12:05'), 725);
+  assert.equal(parseDuration('23:00'), 1380);
+});
+
+test('returns an integer number of minutes', () => {
+  assert.equal(Number.isInteger(parseDuration('2:15')), true);
+});
+
+test('converts the lower boundary 0:00 to 0 minutes', () => {
+  assert.equal(parseDuration('0:00'), 0);
+  assert.equal(parseDuration('00:00'), 0);
+});
+
+test('converts the upper boundary 23:59 to 1439 minutes', () => {
+  assert.equal(parseDuration('23:59'), 1439);
+});
+
+test('throws RangeError when minutes are out of range', () => {
+  assert.throws(() => parseDuration('0:60'), RangeError);
+  assert.throws(() => parseDuration('1:60'), RangeError);
+  assert.throws(() => parseDuration('0:99'), RangeError);
+  assert.throws(() => parseDuration('23:60'), RangeError);
+});
+
+test('throws RangeError when hours are out of range', () => {
+  assert.throws(() => parseDuration('24:00'), RangeError);
+  assert.throws(() => parseDuration('24:59'), RangeError);
+  assert.throws(() => parseDuration('99:00'), RangeError);
+});
+
+test('throws TypeError for non-string input', () => {
+  for (const value of [90, 0, null, undefined, true, {}, [], ['1:30']]) {
+    assert.throws(
+      () => parseDuration(value),
+      TypeError,
+      `expected TypeError for ${String(value)}`,
+    );
+  }
+});
+
+test('throws TypeError for malformed formats', () => {
+  const malformed = [
+    '1:5',
+    '1:234',
+    '01:2',
+    'a:bc',
+    '1:30:00',
+    '',
+    ' 1:30',
+    '1:30 ',
+    '1: 30',
+    '1 :30',
+    '-1:30',
+    '+1:30',
+    '1.5:30',
+    '1:30.5',
+    '1',
+    ':',
+    '1:',
+    ':30',
+    '123:30',
+    '1:30pm',
+    'one:thirty',
+    '\uFF11:\uFF13\uFF10',
+  ];
+  for (const value of malformed) {
+    assert.throws(
+      () => parseDuration(value),
+      TypeError,
+      `expected TypeError for ${JSON.stringify(value)}`,
+    );
+  }
+});