def test_serialize_select_mutiple(browser, app_url):
    """should serialize a select with multiple values into a list"""
    browser.visit(app_url)
    browser.select("pets", ["cat", "dog"])
    form = browser.find_by_name("send")._get_parent_form()
    data = browser.serialize(form)
    assert data["pets"] == ["cat", "dog"]
should serialize a select with multiple values into a list
tests/tests_flask/test_flaskclient.py