There are three types of availability tests:
- URL ping test: a simple test that you can create in the Azure portal.
- Multi-step web test: A recording of a sequence of web requests, which can be played back to test more complex scenarios. Multi-step web tests are created in Visual Studio Enterprise and uploaded to the portal for execution.
- Custom Track Availability Tests: If you decide to create a custom application to run availability tests, the TrackAvailability() method can be used to send the results to Application Insights.
The name URL ping test is a bit of a misnomer. These tests don't use Internet Control Message Protocol (ICMP) to check your site's availability. Instead, they use more advanced HTTP request functionality to validate whether an endpoint is responding. They measure the performance associated with that response. They also add the ability to set custom success criteria, coupled with more advanced features like parsing dependent requests and allowing for retries.
If you selected Parse dependent requests, then all the images, style files, scripts, and other dependent resources must have been received within this period.
Reference:
https://docs.microsoft.com/en-us/azure/azure-monitor/app/monitor-web-app-availability
https://docs.microsoft.com/en-us/azure/azure-monitor/app/monitor-web-app-availability#see-your-availability-test-results
https://docs.microsoft.com/en-us/azure/azure-monitor/app/availability-multistep
https://docs.microsoft.com/en-us/azure/azure-monitor/app/monitor-web-app-availability#success-criteria