The issue was that when using Nock, it is necessary to explicitly end the request stream as following:
req.write(post_data + '\n');
req.end();
Without the 'req.end()', the Nock intercepter will never emit the 'end' event on the response stream making it hang.
For those new to CoffeeScript like myself, it is not enough
req.end
This only compiles to a reference of the 'end' function instead of calling it. To make function call, this works:
req.end '\n'
This compiles to 'req.end('\n') and calls the 'end' function