I have a Cloudflare service and would like to test its http responses. Best I can tell, I should be using wrangler v3's local workerd runtime. There is a sample but it is quite minimal so I have a few sub-questions:
Q1: Do I, somehow, run the service in one workerd nanoservice and run tests in other nanoservices? If so, how do I launch the service from the config.capnp?
Q2: The top of the config.capnp in the unit-tests sample suggests that it may be auto-generated at some point. Is this currently possible or advisable?
Q3: Should I use a service binding to send a fetch request from a test nanoservice to the service it is testing?
Q4: There is mention at https://blog.cloudflare.com/wrangler3/ that vitest integration is progressing. Is there an example of a test which exercises/exorcises a service?
Testing at this level is quite common and test-driven development places a focus on pre-emptive tests so I anticipate that examples and documentation are available. Regrettably, my search found a lot of information on Miniflare v2 but not for the latest Wrangler release and the workerd runtime.
Wrangler exposes an unstable_dev() API which lets you programmatically spin-up Workers and send fetch requests to them, so you can assert the responses are as you expect with your preference of testing framework such as Vitest.
https://developers.cloudflare.com/workers/wrangler/api/
For the available options you can pass to unstable_dev(), refer to UnstableDevOptions.
The Vitest integration you are referring to is the Miniflare environment, where you can access the KV/R2/etc bindings to assert that your Worker is interacting with those properly. That isn't back in Wrangler 3 at the time of writing, but is on the roadmap and will hopefully land in the coming months.