How to Get Asserts To work with Selenium headless mode

[Tom Daria]

Greetings.

I am working with 

C#, 

Chrome browser,
Selenium Web Driver v3.14.1.0

Selenium.WebDriver.ChromeDriver" version="80.0.3987.1600" targetFramework="net461"

I can run my test just fine in Chrome, non headless mode.

But when I switch my configuration to run Selenium in headless mode, none of my Asserts (Driver.Instance.FindElement) work!  

Can anyone help.

Here is the code.

ChromeOptions op = new ChromeOptions();

op.AddArgument("headless");  //don't open a browser but all Asserts fail

op.AddArgument("window-size=1920x1200");

op.AddAdditionalCapability("useAutomationExtension", false);

Instance = new ChromeDriver(ChromeDriverService.CreateDefaultService(), op);

bool review = Driver.Instance.FindElement(By.ClassName("modal-dialog")).Displayed;

review returns false but in non-headless mode it returns true.

Thanks

Tom

[Tom Daria]

This post helped out alot

https://github.com/SeleniumHQ/selenium/issues/4477

After setting these Chrome Options, I am now able to run in headless mode.

                op.AddArgument("--window-size=1920,1080");

                op.AddArgument("--disable-extensions");

                op.AddArgument("--proxy-server='direct://'");

                op.AddArgument("--proxy-bypass-list=*");

                op.AddArgument("--start-maximized");

                op.AddArgument("--headless");

                op.AddArgument("--disable-gpu");

                op.AddArgument("--disable-dev-shm-usage");

                op.AddArgument("--no-sandbox");

                op.AddArgument("--ignore-certificate-errors");