TypeError: Object #<Assertion> has no method 'throw'

I get this error when running my tests on node.js (with Mocha), but it works perfectly in the browser (Chrome 41). `throwException` and `throwError` are working fine.

On node.js, I'm using Mocha 2.2.1 and Expect.js 0.3.1, both from NPM.
In the browser, I'm using Mocha 2.2.1 and Expect.js 0.3.1, both downloaded from the respective GitHub repos.

Reproduce the failure in Node.js using Mocha 2.2.1 and Expect.js 0.3.1, then compare it with the browser setup described in the issue. Trace the assertion API involved in `throw` and verify that the Node.js package exposes the same behavior as the browser build.

Written by the indexing model from the issue text.