def test_element_is_not_visible_return_false(browser, app_url):
    """WebDriverElement.is_not_visible() should return False if element is visible."""
    browser.visit(app_url)

    browser.find_by_css(".show-invisible-element").click()
    assert not browser.find_by_css("#invisible").is_not_visible()
WebDriverElement.is_not_visible() should return False if element is visible.
tests/tests_webdriver/test_element_is_visible.py