test: Add test for Rule class.

[lholmquist]

• This adds two tests for the Rules class testing the error conditions for when a rule does not have an id parameter or a validate function.

While going through #73 and #70 I noticed that this class was missing a couple test cases.

This should bring the test coverage up to 100% for that particular file

[codecov]

Codecov Report

Merging #74 into master will increase coverage by 0.44%.
The diff coverage is n/a.

@@ Coverage Diff @@## master #74 +/- ##
==========================================
+ Coverage 57.14% 57.58% +0.44% 
==========================================
Files 18 18 Lines 448 448 ==========================================
+ Hits 256 258 +2 + Misses 192 190 -2

Impacted Files	Coverage Δ
lib/rule.js	100% <0%> (+15.38%)	⬆️

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[lholmquist]

i must have renamed the files before i sent the PR, but never closed the the old delete file in my editor, so that showed up in a commit. 🤷‍♂️

I forced pushed new changes based on the feedback about using tap.throws

[lholmquist]

Not sure if this one got lost in the flurry of other PR's i sent in :)

Just a friendly ping