Array.from: add a test asserting that it is not enumerable.
Array.from: add tests asserting that it works with primitives.
Fixing dog balls.
Array.from: ensure it works with arraylike objects
Array.from: ensure it swallows negative lengths.
Array.from: ensure it works with basic strings
Array.from: adding some more empty cases
Array.from: Ensuring that the mapper function is only called with two arguments.
Array.from: ensure an object thisArg works
Array.from: ensure a primitive thisArg works
Array.from: remove a redundant test.
Array.from: add (and fix) more tests that throw if the mapper function is provided but not a function.
Array.from: add (and fix) tests ensuring a falsy thisArg is accepted.
Merge pull request #279 from ljharb/array_from_tests

Array.from tests