Mocha this

#### Resolves #1239

Continuing changes from #1344 in a series of quality updates to our test suite, this moves everything into `beforeEach` blocks and uses `this` instead of variables.

**Changes:**
- Fix whitespace
- Move all logic to `beforeEach` blocks
- Switch to using `this` instead of `var`s (thisify all the things)

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### DON'T MERGE BEFORE #1344