Convert unit tests into subtest and to be table-driven

[gpjservais]

This is the final PR addressing refactoring tests from #284. This addresses the following tests:

• TestMatch_IsEmpty
• TestMatch_ValuesEmpty
• TestNumber_EqualNaN
• TestArray_IsEqual/types (split into subtests)
• TestWebsocketMessage_CodeAndType
• TestWebsocketMessage_NoContent

I converted all except TestArray_IsEqual to table driven style. I only split TestArray_IsEqual/types into subtests to address the multiple variable issue.

Also, as noted in the issue, I ended up merging TestNumber_EqualNaN into TestNumber_IsEqual (and also TestNumber_InDelta since half of the test related to InDelta/NotInDelta tests for NaN values). I ended up converting those tests to table-driven format as well.

This is ready for review.

[coveralls]

Coverage: 95.129%. Remained the same when pulling 1465387 on gpjservais:284-refactor-other-unit-tests into 79ad562 on gavv:master.

[gavv]

Thanks!