Add a test for DNT-compliant trackers

[fmarier]

https://bugzilla.mozilla.org/show_bug.cgi?id=1258039

Depends on mozilla/trackertest#6.

[fmarier]

@bensternthal could I please get a review on this new addition to the tracker test page?

[bensternthal]

JS seems ok, 2 things I found:

1. dntcompliant-test took a while to load, I assumed this was a bug (I did not understand the elipses meant loading)
2. Testing locally in private browsing only one bullet is green. (see screenshot)
3. The text states "both of these should be green:" but then there are 3 bullets. Both = 2.

[fmarier]

dntcompliant-test took a while to load, I assumed this was a bug (I did not understand the elipses meant loading)

This should be faster once the file actually exists, but I'll bring the timer down to 3 seconds.

Testing locally in private browsing only one bullet is green. (see screenshot)

That's expected because the whitelist that makes this test pass relies on the URL of the page being itisatrap.org.

The text states "both of these should be green:" but then there are 3 bullets. Both = 2.

Good catch! I'll rephrase this to say that the first two should be green in Fx 42+ and all three should be green in Fx 49+.

[fmarier]

@bensternthal This new version fixes the things you found in #15 (comment).

[bensternthal]

R+