How to fix (some) UnknownError and InvalidArgumentError in Capybara
The other day, our headless system specs in a Ruby on Rails project started failing with a bunch of errors we hadn’t seen before. Mostly Selenium::WebDriver::Error::UnknownError: unknown error: failed to close window in 20 seconds but in some cases also Selenium::WebDriver::Error::InvalidArgumentError: invalid argument: 'handle' must be a string.
Usually random errors in browser tests can be fixed by upgrading selenium-webdriver, Chrome, chromedriver or any combination thereof, but not this time.