diff --git a/tests/test_util.py b/tests/test_util.py
new file mode 100644
index 00000000..df114597
--- /dev/null
+++ b/tests/test_util.py
@@ -0,0 +1,147 @@
+from __future__ import annotations
+
+import os
+import subprocess
+import zipfile
+from datetime import datetime
+
+import pytest
+
+from util import create_valid_filename
+from util import get_ogg_and_duration
+from util import get_song_cover_path
+
+
+@pytest.mark.parametrize(
+    'file_names, expected_output', [
+        # Both .ogg and clip1.ogg exists
+        (['file1.ogg', 'file2.clip1.ogg'], ('file2.clip1.ogg', '10')),
+        (['file1.ogg'], (None, None)),  # Only .ogg exists, no clip1.ogg
+        ([], (None, None)),  # No files
+    ],
+)
+def test_get_ogg_and_duration(file_names, expected_output, tmpdir, mocker):
+    folder_path = tmpdir.mkdir('audio_files')
+    for file_name in file_names:
+        folder_path.join(file_name).write('fake_audio_data')
+
+    mocker.patch('subprocess.check_output', return_value='10')
+
+    ogg_file, duration_str = get_ogg_and_duration(str(folder_path))
+
+    if ogg_file:
+        ogg_file = os.path.basename(ogg_file)
+
+    assert (ogg_file, duration_str) == expected_output
+
+
+def test_get_ogg_and_duration_subprocess_error(tmpdir, mocker):
+    folder_path = tmpdir.mkdir('audio_files')
+    folder_path.join('file.clip1.ogg').write('fake_audio_data')
+
+    mocker.patch(
+        'subprocess.check_output',
+        side_effect=subprocess.CalledProcessError(1, 'cmd'),
+    )
+
+    ogg_file, duration_str = get_ogg_and_duration(str(folder_path))
+
+    assert (ogg_file, duration_str) == (None, None)
+
+
+@pytest.mark.parametrize(
+    'file_names, expected_output', [
+        (
+            ['jk_song1_b.png', 'jk_song2_b.png'],
+            'jk_song1_b.png',
+        ),  # Multiple matching files
+        (['jk_song1_b.png'], 'jk_song1_b.png'),  # Single matching file
+        (['song1_b.png', 'jk_song1.png'], None),  # No matching files
+        ([], None),  # Empty folder
+    ],
+)
+def test_get_song_cover_path(file_names, expected_output, tmpdir):
+    folder_path = tmpdir.mkdir('cover_files')
+    for file_name in file_names:
+        folder_path.join(file_name).write('fake_image_data')
+
+    cover_file = get_song_cover_path(str(folder_path))
+
+    if cover_file:
+        cover_file = os.path.basename(cover_file)
+
+    assert cover_file == expected_output
+
+
+@pytest.mark.parametrize(
+    'input_string, expected_output', [
+        # Special characters should be removed
+        ('file$name1.txt', 'filename1txt'),
+        # Spaces should remain, trailing spaces should be removed
+        ('  file name  ', '  file name'),
+        # Slash should be preserved as it's in valid_chars
+        ('file/name', 'filename'),
+        # File name should be truncated to 255 characters
+        ('long' * 80, 'long' * 63 + 'lon'),
+    ],
+)
+def test_create_valid_filename(input_string, expected_output):
+    result = create_valid_filename(input_string)
+    assert result == expected_output
+
+
+def datetime_to_ticks(dt):
+    epoch = datetime(1, 1, 1)
+    dt_delta = dt - epoch
+    ticks = dt_delta.total_seconds() * 10 ** 7
+    return int(ticks)
+
+
+def yyyymmdd_to_ticks(date_str: str):
+    dt = datetime.strptime(date_str, '%Y%m%d')
+    return datetime_to_ticks(dt)
+
+
+def zipdir(path, ziph, archiveroot):
+    for root, dirs, files in os.walk(path):
+        for file in files:
+            actual_file_path = os.path.join(root, file)
+            archive_file_path = os.path.join(
+                archiveroot, os.path.relpath(actual_file_path, path),
+            )
+            ziph.write(actual_file_path, archive_file_path)
+
+
+@pytest.mark.parametrize(
+    'input_datetime, expected_ticks', [
+        (datetime(1, 1, 1), 0),
+        (datetime(1970, 1, 1), 621355968000000000),
+    ],
+)
+def test_datetime_to_ticks(input_datetime, expected_ticks):
+    assert datetime_to_ticks(input_datetime) == expected_ticks
+
+
+@pytest.mark.parametrize(
+    'input_date_str, expected_ticks', [
+        ('00010101', 0),
+        ('19700101', 621355968000000000),
+    ],
+)
+def test_yyyymmdd_to_ticks(input_date_str, expected_ticks):
+    assert yyyymmdd_to_ticks(input_date_str) == expected_ticks
+
+
+def test_zipdir(tmp_path):
+    test_folder = tmp_path / 'test_folder'
+    test_folder.mkdir()
+    test_file = test_folder / 'test_file.txt'
+    test_file.write_text('Hello, world!')
+
+    zip_path = tmp_path / 'test_folder.zip'
+    with zipfile.ZipFile(zip_path, 'w') as ziph:
+        zipdir(test_folder, ziph, 'archive_root')
+
+    with zipfile.ZipFile(zip_path, 'r') as ziph:
+        with ziph.open('archive_root/test_file.txt') as f:
+            assert f.read().decode() == 'Hello, world!'