How to run unit tests for code that uses App Engin

Question

I was told the best solution to run unit tests for code that uses App Engine services such as datastore or memcache was to run the development server in a child process, but I'm not sure how. Anybody successfully ran this kind of test and can share a solution?

App Engine SDK for Go uses the Python dev_appserver; see this thread.

Answer 1

You should check out Google App Engine Go testing library by Josh Marsh.

Answer 2

I know the questioner wants to build a testbed and needs to do this, but I think there's another approach worth mentioning here.

Besides using a testbed for the GAE services, Go's interesting nature also opens up another possibility: write your application to just require objects that have the interfaces that you use (they'd be a subset of the official APIs) and mock them out when testing. This requires you to be doing some amount of dependency injection of some sort, but that's a really good idea anyway.

Once the interfaces the interfaces are written, you can mock them using a library like gomock.

Answer 3

An interesting development, as of 1.8.6 using service stubs has been integrated into the SDK through the "appengine/aetest" package. More info