[HTTPS-Everywhere] Recommendations for testing only changed rules

[Jacob Hoffman-Andrews]

Hi all,

Right now our automated ruleset test on Travis only tests that updated
rulesets have sufficient test coverage. Ideally I'd like it to also run
a fetch test to make sure all domains exist, answer on 443, and provide
a success response (and eventually, test for mixed content).

However, running a fetch test for all rulesets on all pull requests
would take too long. So I'd like to make pull requests on Travis test
only the rules changed in that pull request. Has anyone done this? Any
suggestions?

One confounding factor: Travis does a shallow clone, so it's not trivial
to do a diff --name-only against origin/master. I've tried adding a
fetch command to the test, but no luck so far.