Question

We are implementing a functional/regression testing system at work to test our services (our app is setup using a client/server architecture).

How do you start? Do you build some test cases? What about starting a new feature? Would all the test cases go into one file (we are using mocha and node.js)?

Answer 1

For regressions, you should start from the parts of your system that actually work and show no bugs. You write some test cases against that part, and re-do them on future relases to ensure that the application is always working in the right way.

http://en.wikipedia.org/wiki/Regression_testing

I suggest using some form of automation, to ensure you always do the same checks in the exact way.
Here’s a list of common used softwares

http://en.wikipedia.org/wiki/Test_automation#Notable_test_automation_tools