I was looking for something like this to test if I could watch purchased Amazon videos in HD, but I didn't really want to download and install anything to my machine.
Amazon actually has a free video linked to in their documentation which can give you an idea of whether your setup supports HDCP. One thing that it doesn't seem to do is explain why your setup doesn't support it. (I think in my case it's my dual monitor setup again.)
December 2020 update
The text of the now removed documentation page, from archive.org:
HDCP for Amazon Video on Computers
You can only stream Amazon Video content in HD through your computer's web browser if your computer and connected display screen(s) meet HDCP requirements.
You can check whether your computer is HDCP-compliant by playing this free movie. Use the video player's HD indicator to determine if your device meets requirements:
- If the HD indicator is illuminated, HDCP requirements have been met and the video is playing in HD.
- If the HD indicator is dim, HDCP requirements have been met, but the video isn’t playing in HD because your Internet connection isn’t fast enough.
- If the HD indicator is disabled, HDCP requirements have not been met and the video is playing in SD. Hover your mouse over the HD indicator to see a message explaining why HDCP requirements have not been met.
Note: Some Video Graphics Array (VGA) and Digital Visual Interface (DVI) connections and monitors don't support HDCP, which may prevent your computer from meeting HDCP requirements.
For more information, go to System Requirements for Streaming on Your Computer.
So if you can find a free, HD video on Amazon Prime Video, it sounds like you can verify HDCP on your machine.