bespoken/virtual-alexa

Makes sense. I ended up just mocking the persistence layer with a fake persistence adapter.

I have a dedicated persistence.js module with a method getPersistenceAdapter. That initializes my S3PersistenceAdapter with a bucket name (and any other settings) and is called during the custom skill initialization.

In test I use sinon to stub out that method.

  stubPersistenceAdapter(sinon.stub(persistence, 'getPersistenceAdapter'));

I then pass that into the method below to get a standard mock for the persistence adapter

/**
 * Creates a consistent stub for the persistence adapter which saves/loads attributes
 * @param stub - a sinon stub which has stubbed the getPersistenceAdapter
 * @returns a sinon stub which has been setup as a persistence adapter
 */
export const stubPersistenceAdapter = (stub) => {
  let savedAttributes = null;
  stub.returns({
    getAttributes: (requestEnvelope) => { return Promise.resolve(savedAttributes);},
    saveAttributes: (requestEnvelope, attributes) => {
      savedAttributes = attributes;
      return Promise.resolve();
    }
  });
  stub.getSavedAttributes =  () => savedAttributes;
  stub.setSavedAttributes = (val) => savedAttributes = val;
  return stub;
};

The nice thing about this solution is that it works regardless of the persistence layer (S3, Dymamo, custom?). It also allows me to get/set the attributes that have been written so that I can examine them directly in my tests. Most of my unit tests look at the responseBuilder generated output from the handler as well as the data written to persistence. In all cases I can easily populate that data before the test runs.

Anyway, that's what's worked for me so far :)