I have a mobile application backend developed with node.js express. I tried it to deploy it as lambda service. For that I created a Serverless Framework project (https://github.com/serverless). Previously I tested mobile app locally by starting express backend application. Now I can't find a method to test my mobile app locally without local backend.
It doesn't look like there's way to do this right now, but version 1.4.0 is about to be released and, among other things, it should include a new command "jaws serve" which should address your problem.
Here's the PR: https://github.com/jaws-framework/JAWS/pull/269
UPDATE: you can now use the new serverless-serve plugin for this.
UPDATE 2: serverless-serve hasn't been updated in a while, it looks like serverless-offline is a much better option now to emulate Lambda functions.