diff --git a/tests/test_cleanmedia.py b/tests/test_cleanmedia.py
new file mode 100644
index 0000000..3b20629
--- /dev/null
+++ b/tests/test_cleanmedia.py
@@ -0,0 +1,181 @@
+"""Tests for cleanmedia module."""
+
+from datetime import datetime, timedelta
+from typing import Any, Tuple
+
+import pytest
+from pytest_mock import MockerFixture
+
+from cleanmedia import File, MediaRepository
+
+
+@pytest.fixture
+def mock_db_conn(mocker: MockerFixture) -> Tuple[Any, Any]:
+    """Create mock database connection and cursor.
+
+    Args:
+        mocker: pytest-mock fixture
+
+    Returns:
+        Tuple of mock connection and cursor
+    """
+    conn_mock = mocker.Mock()
+    cursor_mock = mocker.Mock()
+    ctx_manager = mocker.Mock()
+    ctx_manager.__enter__ = mocker.Mock(return_value=cursor_mock)
+    ctx_manager.__exit__ = mocker.Mock(return_value=None)
+    conn_mock.cursor.return_value = ctx_manager
+    return conn_mock, cursor_mock
+
+
+@pytest.fixture
+def media_repo(tmp_path: Any, mock_db_conn: Tuple[Any, Any], mocker: MockerFixture) -> MediaRepository:
+    """Create MediaRepository instance with mocked database connection.
+
+    Args:
+        tmp_path: pytest temporary directory fixture
+        mock_db_conn: Mock database connection fixture
+        mocker: pytest-mock fixture
+
+    Returns:
+        Configured MediaRepository instance
+    """
+    conn_mock, _ = mock_db_conn
+    media_path = tmp_path / "media"
+    media_path.mkdir()
+    mocker.patch("cleanmedia.MediaRepository.connect_db", return_value=conn_mock)
+    return MediaRepository(media_path, "postgresql://fake")
+
+
+def test_file_init(mocker: MockerFixture) -> None:
+    """Test File class initialization."""
+    repo = mocker.Mock()
+    file = File(repo, "mxid123", 1600000000, "base64hash123")
+    assert file.media_id == "mxid123"
+    assert file.create_date == datetime.fromtimestamp(1600000000)
+    assert file.base64hash == "base64hash123"
+    assert file.repo == repo
+
+
+def test_file_fullpath(media_repo: MediaRepository) -> None:
+    """Test File.fullpath property returns correct path."""
+    file = File(media_repo, "mxid123", 1600000000, "abc123")
+    expected_path = media_repo.media_path / "a" / "b" / "c123"
+    assert file.fullpath == expected_path
+
+
+def test_file_fullpath_none_if_no_hash(media_repo: MediaRepository) -> None:
+    """Test File.fullpath returns None when hash is empty."""
+    file = File(media_repo, "mxid123", 1600000000, "")
+    assert file.fullpath is None
+
+
+def test_file_exists(media_repo: MediaRepository) -> None:
+    """Test File.exists returns True when file exists."""
+    file = File(media_repo, "mxid123", 1600000000, "abc123")
+    file_path = media_repo.media_path / "a" / "b" / "c123"
+    file_path.mkdir(parents=True)
+    (file_path / "file").touch()
+    assert file.exists() is True
+
+
+def test_file_not_exists(media_repo: MediaRepository) -> None:
+    """Test File.exists returns False when file doesn't exist."""
+    file = File(media_repo, "mxid123", 1600000000, "abc123")
+    assert file.exists() is False
+
+
+def test_file_delete(media_repo: MediaRepository, mock_db_conn: Tuple[Any, Any]) -> None:
+    """Test File.delete removes files and database entries."""
+    _, cursor_mock = mock_db_conn
+    file = File(media_repo, "mxid123", 1600000000, "abc123")
+
+    file_path = media_repo.media_path / "a" / "b" / "c123"
+    file_path.mkdir(parents=True)
+    (file_path / "file").touch()
+    (file_path / "thumb").touch()
+
+    assert file.delete() is True
+    assert not file_path.exists()
+
+    cursor_mock.execute.assert_any_call("DELETE from mediaapi_thumbnail WHERE media_id=%s;", ("mxid123",))
+    cursor_mock.execute.assert_any_call("DELETE from mediaapi_media_repository WHERE media_id=%s;", ("mxid123",))
+
+
+def test_get_single_media(media_repo: MediaRepository, mock_db_conn: Tuple[Any, Any]) -> None:
+    """Test MediaRepository.get_single_media returns correct File object."""
+    _, cursor_mock = mock_db_conn
+    cursor_mock.fetchone.return_value = ("mxid123", 1600000000000, "abc123")
+
+    file = media_repo.get_single_media("mxid123")
+    assert file is not None
+    assert file.media_id == "mxid123"
+    assert file.base64hash == "abc123"
+
+    cursor_mock.execute.assert_called_with(
+        "SELECT media_id, creation_ts, base64hash from mediaapi_media_repository WHERE media_id = %s;",
+        ("mxid123",),
+    )
+
+
+def test_get_single_media_not_found(media_repo: MediaRepository, mock_db_conn: Tuple[Any, Any]) -> None:
+    """Test MediaRepository.get_single_media returns None when media not found."""
+    _, cursor_mock = mock_db_conn
+    cursor_mock.fetchone.return_value = None
+
+    file = media_repo.get_single_media("mxid123")
+    assert file is None
+
+
+def test_clean_media_files(media_repo: MediaRepository, mock_db_conn: Tuple[Any, Any]) -> None:
+    """Test MediaRepository.clean_media_files deletes old files."""
+    _, cursor_mock = mock_db_conn
+
+    old_date = int((datetime.now() - timedelta(days=31)).timestamp())
+    new_date = int((datetime.now() - timedelta(days=1)).timestamp())
+
+    cursor_mock.fetchall.return_value = [
+        ("old_file", old_date * 1000, "abc123"),
+        ("new_file", new_date * 1000, "def456"),
+    ]
+
+    media_repo._avatar_media_ids = []
+
+    num_deleted = media_repo.clean_media_files(30, False, False)
+    assert num_deleted == 1
+
+
+def test_clean_media_files_dryrun(media_repo: MediaRepository, mock_db_conn: Tuple[Any, Any]) -> None:
+    """Test MediaRepository.clean_media_files in dry run mode."""
+    _, cursor_mock = mock_db_conn
+
+    old_date = int((datetime.now() - timedelta(days=31)).timestamp())
+    cursor_mock.fetchall.return_value = [
+        ("old_file", old_date * 1000, "abc123"),
+    ]
+
+    media_repo._avatar_media_ids = []
+
+    num_deleted = media_repo.clean_media_files(30, False, True)
+    assert num_deleted == 1
+
+
+def test_sanity_check_thumbnails(media_repo: MediaRepository, mock_db_conn: Tuple[Any, Any], caplog: Any) -> None:
+    """Test MediaRepository.sanity_check_thumbnails logs correct message."""
+    _, cursor_mock = mock_db_conn
+    cursor_mock.fetchone.return_value = (5,)
+
+    media_repo.sanity_check_thumbnails()
+    assert "You have 5 thumbnails in your db that do not refer to media" in caplog.text
+
+
+def test_get_avatar_images(media_repo: MediaRepository, mock_db_conn: Tuple[Any, Any]) -> None:
+    """Test MediaRepository.get_avatar_images returns correct list."""
+    _, cursor_mock = mock_db_conn
+    cursor_mock.fetchall.return_value = [
+        ("mxc://matrix.org/abc123",),
+        ("mxc://matrix.org/def456",),
+    ]
+
+    avatar_ids = media_repo.get_avatar_images()
+    assert avatar_ids == ["abc123", "def456"]