Provide testable log/events facilities to assert to during the test

[ppxl]

Using the go test mechanism in conjuncion with testcluster-go is the go-to (pun intended) of this project. Asserting information of logs and events should be the main point to get a better testing experience.

My idea is something along the lines of this pseudo-code:

func Test_myOperator(t *testing.T, c *testCluster) {
  // given
  err := c.Apply(operatorYaml)
  require.NoError(t, err)

  // when
  err := c.Apply(aristotelesCustomResource)
  require.NoError(t, err)

  // then
  within(10 * time.Seconds, func() error
     lo := c.Lookout("k8s.example.com/v1/YourResource", "v1/Pod")
     events := lo.Resource(YourResource).ByName("aristoteles").Events(t) // handle should fail with errors to reduce the mental load
     events.Contains("Quality is not an act, it is a habit.") // types and issuer should play into this as well
     
     arisPod := lo.Resource(Pod).BySelector("app:aristoteles")
     status := arisPod.Status(t)
     status.Contains("Running") // could be more specific to certain status fields?

     logs := arisPod.Logs(t)
     logs.Contains("Pod started successfully on port 1234")
  )
}

Edit: I figure this is rather an architecture design issue, but here goes. These are the key points:

• Resource selection must be achived (here: the look-out who sits in the crow's nest of your ship)
• The selected resource is imaged as an object that receives *testing.T in order to
  • control the test failure/success,
  • avoid helper files in the stacktrace,
  • and finally allow to include a comfy assertion framework
• added value of this is inspection and assertion of resource attributes during the test run-time
• ideas of functors
  • Events() - events provided to the requested resource
  • Logs() - pod logs - how to separate by container? what about init - or crashlooped containers?
  • Status() - has every resource a general status? most probably not
    • probably do some type cast or generic magic to return the desired type previously mentioned as GVK. Maybe the expected golang type from the CRD type is better for casting)
  • Timeout() - eventual consistency makes timeout of tests necessary
  • each functor allows
    • at least generic assertions like those from stretchr/testify
    • a DSL way of allowing to enhance assertions to aid more use-case/business-specific needs