Keep Mocha tests alongside to source files

I currently have my NodeJS source files in src and test suites in test, e.g.:

/src/bar/baz/foo.js
/test/bar/baz/foo.spec.js

This leads to awkward require statements like var foo = require('../../../src/bar/baz/foo'). And it's hard to see at a glance which source files are missing tests. I would like to instead keep my test suites in the same directory as the relevant source files:

/src/bar/baz/foo.js
/src/bar/baz/foo.spec.js

But now running mocha --recursive src causes errors as Mocha tries to run my source files as tests.

I've seen suggestions of using find or gulp to filter the file list but I find it surprising that this can't be done with plain Mocha. What's the recommended way of organising files this way?