Convert typings tests to tsd

[shadowspawn]

Pull Request

Problem

Using a TypeScript compile (tsc) to test the TypeScript typings was useful, but some minor annoyances:

• felt a bit strange writing lots of fake code
• declaring lots of unused variables to do return type checking
• suppressing lint warnings from the dummy code, like the unused variables!
• type checking by assignment is not strict

Solution

Use tsd for a fairly direct conversion to strict type tests. Instead of assigning to a typed variable, use expectType.

One related change: tsd complained about using typings property in package.json, and in fact types is more standard so changed to use that.

ChangeLog

• make TypeScript typings tests stricter (Convert typings tests to tsd #1453)

[abetomo]

Cool!