diff --git a/src/main.py b/src/main.py
index bfc1488..37e9368 100644
--- a/src/main.py
+++ b/src/main.py
@@ -20,16 +20,16 @@ logger = setup_logger(__name__)
 
 load_dotenv()
 
-LOCAL_SYNC_FILE = "calendar_sync.json"
-CALDAV_URL = os.getenv("CALDAV_URL")
-CALDAV_USERNAME = os.getenv("CALDAV_USERNAME")
-CALDAV_PASSWORD = os.getenv("CALDAV_PASSWORD")
-CALDAV_CALENDAR_NAME = os.getenv("CALDAV_CALENDAR_NAME")
-GOOGLE_CALENDAR_NAME = os.getenv("GOOGLE_CALENDAR_NAME")
-
 
 def main() -> None:
     """Run the calendar synchronization process."""
+    LOCAL_SYNC_FILE = "calendar_sync.json"
+    CALDAV_URL = os.getenv("CALDAV_URL")
+    CALDAV_USERNAME = os.getenv("CALDAV_USERNAME")
+    CALDAV_PASSWORD = os.getenv("CALDAV_PASSWORD")
+    CALDAV_CALENDAR_NAME = os.getenv("CALDAV_CALENDAR_NAME")
+    GOOGLE_CALENDAR_NAME = os.getenv("GOOGLE_CALENDAR_NAME")
+
     try:
         logger.info("Starting calendar synchronization process")
 
diff --git a/tests/test_main.py b/tests/test_main.py
new file mode 100644
index 0000000..a3cd139
--- /dev/null
+++ b/tests/test_main.py
@@ -0,0 +1,98 @@
+"""Tests for the main module."""
+
+from unittest.mock import MagicMock, patch
+
+import pytest
+
+from src.main import main
+
+
+@pytest.fixture
+def mock_env_vars(monkeypatch):
+    """Fixture to mock environment variables."""
+    monkeypatch.setenv("CALDAV_URL", "http://mock-caldav-url.com")
+    monkeypatch.setenv("CALDAV_USERNAME", "mock_user")
+    monkeypatch.setenv("CALDAV_PASSWORD", "mock_password")
+    monkeypatch.setenv("CALDAV_CALENDAR_NAME", "Mock CalDAV Calendar")
+    monkeypatch.setenv("GOOGLE_CALENDAR_NAME", "Mock Google Calendar")
+
+
+@patch("src.main.authenticate_google")
+@patch("src.main.search_calendar_id")
+@patch("src.main.connect_to_caldav")
+@patch("src.main.get_calendar")
+@patch("src.main.fetch_events")
+@patch("src.main.load_local_sync")
+@patch("src.main.compare_events")
+@patch("src.main.add_event_to_google")
+@patch("src.main.delete_event_from_google")
+@patch("src.main.save_local_sync")
+def test_main(  # noqa PLR0913
+    mock_save_local_sync,
+    mock_delete_event_from_google,  # noqa ARG001
+    mock_add_event_to_google,
+    mock_compare_events,
+    mock_load_local_sync,
+    mock_fetch_events,
+    mock_get_calendar,
+    mock_connect_to_caldav,
+    mock_search_calendar_id,
+    mock_authenticate_google,
+    mock_env_vars,  # noqa ARG001
+):
+    """Test the main function with mocked dependencies."""
+    # Mock returns
+    mock_authenticate_google.return_value = "mock_service"
+    mock_search_calendar_id.return_value = "mock_google_calendar_id"
+    mock_connect_to_caldav.return_value = "mock_principal"
+    mock_get_calendar.return_value = MagicMock(name="Mock CalDAV Calendar")
+    mock_fetch_events.return_value = [{"uid": "event1"}, {"uid": "event2"}]
+    mock_load_local_sync.return_value = [{"uid": "event1"}]
+    mock_compare_events.return_value = (
+        [{"uid": "event2"}],  # new events
+        [],  # updated events
+        [],  # deleted events
+    )
+
+    # Call the main function
+    main()
+
+    # Assert calls
+    mock_authenticate_google.assert_called_once()
+    mock_search_calendar_id.assert_called_once_with("mock_service", "Mock Google Calendar")
+    mock_connect_to_caldav.assert_called_once_with(
+        "http://mock-caldav-url.com",
+        "mock_user",
+        "mock_password",
+    )
+    mock_get_calendar.assert_called_once_with("mock_principal", "Mock CalDAV Calendar")
+    mock_fetch_events.assert_called_once_with(mock_get_calendar.return_value)
+    mock_load_local_sync.assert_called_once_with("calendar_sync.json")
+    mock_compare_events.assert_called_once_with(
+        mock_load_local_sync.return_value,
+        mock_fetch_events.return_value,
+    )
+    mock_add_event_to_google.assert_called_once_with(
+        "mock_service",
+        {"uid": "event2"},
+        "mock_google_calendar_id",
+    )
+    mock_save_local_sync.assert_called_once_with(
+        "calendar_sync.json",
+        mock_fetch_events.return_value,
+    )
+
+
+@patch("src.main.logger.error")
+def test_main_exception(mock_logger_error, mock_env_vars):  # noqa ARG001
+    """Test the main function handles exceptions gracefully."""
+    with (
+        patch("src.main.authenticate_google", side_effect=Exception("Mock error")),
+        pytest.raises(Exception, match="Mock error"),
+    ):
+        main()
+
+    mock_logger_error.assert_called_once_with(
+        "Error occurred during sync: Mock error",
+        exc_info=True,
+    )