How can AdMob mediation in Android be tested?

Question

I have an app with rewarded video ads. I'm using mediation through AdMob to show ads through different ad networks. My app is set up correctly and all ads are showing as they should be. So my issue is that I need to occasionally test an individual ad network for issues. Maybe there is a leak or crash or bad ads showing up. The problem is I can't find a way in AdMob mediation to remove or disable AdMob network from the Waterfall. I changed the eCPM to 0.01 and set the network I want to test to $1000 but AdMob network ads still show up to the exclusion of the other ads. If I'm testing MoPub ads then I want to see only MoPub test ads (#igetbeggin).

Attempted solution 1: Use a test AdMob ID in app. This fails because in this case AdMob bypasses mediation settings and only shows test ads from the AdMob network. All other ad networks you can give custom test IDs in the Waterfall but not AdMob.

Attempted solution 2: Change eCPM of AdMob network to 0.01 in Waterfall. The problem with this solution is that if there is a error from a higher network it will still access ads from the AdMob network. In this case it will be a live ad because the test Ad ID is not being used (ID is not changeable). This now risks being smite from the Google Gods high above. Due to violating terms of service and testing with live ads.

Attempted solution 3: Disable AdMob ads based on location. I found some sites suggesting this during research but it seems to be no longer possible. Even if it was I don't want to disable ads for the production version of our app.

Answer 1

Here's something that checks for ad load errors, not sure if it answers your question though.

https://developers.google.com/admob/android/ad-load-errors