Saturday, October 12, 2013

Remeber to Reset IE Zoom (Selenium Web Driver + JUnit + ExtJS)

If you are unlucky as me, you may be doing research of this error message right now:

org.openqa.selenium.remote.SessionNotFoundException: Unexpected error launching Internet Explorer. Browser zoom level was set to 125%. It should be set to 100% (WARNING: The server did not provide any stacktrace information)

Everything was working perfectly, and all tests passed with green color. Then all of a sudden all test cases failed with the error above. It's very a clear error message, and you don't need any research to fix the problem. Just open IE and visit the website under test, then set zoom level to 100%. Then all tests should pass again (of course, only if they were passing before).

However, I do not want to ensure zoom level before every test runs, so I found the following code snippet to ask Selenium WebDriver to ignore IE zoom level:
Things were quiet for a while until I was hit by a strange error message about object not clickable. Of course, when I put it in context, you knew I should check for zoom level immediately. However, in real life, it threw me a big loop, and I spent a good hour researching how to click ExtJS component or related catches that I may not know before. Until, I accidentally saw the zoom level is not 100%. Now after I reset zoom level back to 100%, problem is gone. I imagine WebDriver has some coordinate conversion issue when IE's zoom level is 100%.

So what is the conclusion? Two bullet points for IE testing:

  • Do NOT use the code snippet above to ignore zoom level
  • Always ensure zoom level is 100%

1 comment:

Dave said...

You can set the driver to ignore the zoom level and it will work if you also set EnableNativeEvents to false. See this post Ignoring IE Driver Zoom Requirement