Coverage checking does not check target hosts

[jsha]

If a test URL is included in a ruleset, but that test URL is not covered by any target host, the checker will not flag an error. See, for instance, https://github.com/EFForg/https-everywhere/pull/1188.

getCoverageProblems should check test URLs against target hosts and flag such problems.

[krngrvr09]

Hi @jsha, I was able to reproduce this problem. Can we use a library tldextract to check test URLs against target hosts. We can ignore the subdomains and suffixes, and just consider the domain. What do you think?

Here is the sample code:

>>> tldextract.extract('http://www.iiitd.edu.in')
ExtractResult(subdomain='www', domain='iiitd', suffix='edu.in')

[jsha]

Hi Karan,

According to https://github.com/hiviah/https-everywhere-checker/issues/13, there is already an implementation of the needed code in RuleTrie, but I accidentally bypassed it in #4.