WPT does not load advertisements?

Hey folks,

I’m analyzing my website performance under different advertisement providers (or even specific ads), as some of them take a lot of resources or a long time to load/render and affects end-users.
Does WPT prevents advertisements to load or are some endpoints blacklisted? I can’t see the ad on the screenshots even after setting minimum test duration to 20 seconds.

Same issue repros on other sites (example: MSN.com https://www.webpagetest.org/result/160920_96_3Z5/). After 20 seconds, the test doesn’t show ads either in screenshots or the video, yet loading it shows a top ad and a side ad after less than 10 seconds on my connection.

Is this by design? Am I missing something?

Try turning on the “preserve user agent string” option to avoid adding the PTST/ver string to the UA string. I know the AOL ad network for example doesn’t serve ads when it sees it.