I am testing a Chrome extension which requires the user to be logged in to use, but I cannot figure out how to login with my test account. I have tried logging in to accounts.google.com but this is apparently insufficient; as far as the chrome APIs are concerned there is no authenticated user.
Chrome keeps prompting for login at chrome://chrome-signin but because I can't view the html of the page I can't determine what elements to interact with in Selenium to use it.
You may need to login manually once and then use that for automation. Try below code , may be it help you:
System.setProperty("webdriver.chrome.driver","<chrome exe path>");
ChromeOptions options = new ChromeOptions();
options.addArguments("user-data-dir= <full local path Google Chrome user data default folder>);
WebDriver driver = new ChromeDriver(options);
driver.get("https://mail.google.com");
Login once manually when browser launched.
Then re-run script now it should use previous login.
Hope it will help you.