Most basic way of testing adding a local npm project to a local meteor package.
To use:
you@yourmachine:~$ git clone https://github.com/mattsouth/meteor-ref.git
you@yourmachine:~$ cd meteor-ref
check that the npm project is usable...
you@yourmachine:~$ node
> console.log(require('./my-npm-project').msg)
Hello World!
If you see the Hello World! then it works. It's ctrl-D to escape the node REPL. Now we need to install the node package to the meteor package.
you@yourmachine:~$ cd my-meteor-package
you@yourmachine:~$ meteor npm install '../my-npm-project'
This will show an error because you dont have a package.json file but it will install your package so that you can now run the tests..
you@yourmachine:~$ meteor test-packages ./
You should see green tests at http://localhost:3000