test: Add redis tests for invalidation

[jhonrocha]

I have created a file for redis invalidation tests Closes #59

[jhonrocha]

@simone-sanfratello There are 7 tests inside "invalidate" on async-cache-dedupe. On this PR I covered the first 3. The other 4 test cases are directly related to the async-cache-dedupe library, so I would need to use its instance to test methods like storage.store.smembers.

For doing that, I believe I can use a stub. Is that the expectation here?

I would like to cover other cases instead, like policy~skip, policy~extendKey, skip.

[simone-sanfratello]

using an actual redis db, you can read what's inside and replicate the tests from async-cache-dedupe, and of course feel free to add more tests!

[jhonrocha]

Got it!! Working on that now. One more question, though: the clean way to run Redis is through a service, but that will limit the CI to a Linux runner. Is that okay?

[simone-sanfratello]

Got it!! Working on that now. One more question, though: the clean way to run Redis is through a service, but that will limit the CI to a Linux runner. Is that okay?

yes, you can see an example on async-cache-dedupe or fastify-redis

[jhonrocha]

Got it. Simone, the invalidation function is async and it is not awaited, so I can only think in hackish ways to await for it to be executed. An example of the problem would be this:

    // Request a mutation that clear 'gets' references
    await app.inject({
      ...defaultPost,
      body: { query: 'mutation { set(id: 11) }' }
    })

    // This fails, the invalidate was not called yet 
    t.equal((await redisClient.smembers('r:gets')).length, 0)
    t.equal((await redisClient.smembers('r:get:11')).length, 0)

Do you think it is a good idea to add an event onInvalidate to be called after invalidation ?