successful_checks is always empty for AVIF

[leo-barnes]

Describe the issue
When compiling the latest ComplianceWarden and running it on an AVIF file with JSON output, the "successful_checks" array is always empty.

Detailed analysis
From comparing the avif.cpp rules to the av1_hdr10plus.cpp rules, the latter seem to be using out->covered();. I'm assuming this is the snippet that marks the rule as successfully checked.

This would be required in order to implement AOMediaCodec/av1-avif#219

[leo-barnes]

Yup, the out->covered(); calls seem to be the issue.

[rbouqueau]

Indeed. You can add them based on the code (+ the coverage report you can generate with this script).