how_do_i_stub_requires.js

var Foo = require('../foo/index.js');

var someClass = new SomeClass({
  someMethod: function () {
    // How do I stub this without requiring it to be set on the prototype?
    // ex: w/o having it set on someClass.baz = Foo.bar();
    var baz = Foo.bar();
    if (baz == 'hello') {
      return 1
    }
    else {
      return 0
    }
  }
});

Main issue is that the require is already "compiled" by the time it gets to the tests (otherwise the tests wouldnt run) so I can't really overwrite require() even

OK, if the issue is stubbing something internally required by another module, then you'll need proxyquireify, a browserify-specific version of proxyquire.

That'd let you do something like:

var SomeClassStub = Sinon.stub();
var Foo = proxyquire('../foo/index.js', { './someClass': SomeClassStub });

So now, internal to the Foo module, the require to ./someClass will resolve to your stub. Hooray. All the power of Jest with the flexibility of Sinon - and it works in the browser too!

Here's an example of not-real test code with Browserify, Mocha, Sinon running in a Karma harness: https://github.com/jmreidy/react-combobox/blob/master/test/combobox.test.js. Main code:

var proxyquire = require('proxyquireify')(require);
describe('Combobox', function () {
  var instance, stubOption;
  beforeEach(function () {
    stubOption = sinon.stub();
    instance=proxyquire('../lib/combobox', {
      './option': stubOption
    });
  });

Presumably proxyquireify would work anywhere you're successfully packaging Browserify bundled code/tests. (So Jasmine should be fine.)

Note that the karma example above is relying on a key karma plugin, or at least my fork of it: https://github.com/jmreidy/karma-browserifast