
def pytest_addoption(parser):
    parser.addoption("--webdriver", action="store", default="None",
                     help=("Selenium WebDriver interface to use for running the test. "
                           "Choices: None, PhantomJS, Chrome, Firefox, ChromeHeadless, "
                           "FirefoxHeadless. Alternatively, it can be arbitrary Python code "
                           "with a return statement with selenium.webdriver object, for "
                           "example 'return Chrome()'"))
