Unit testing with client-go

[briantopping]

Getting some experience with RIO, having problems testing: According to to this issue, client-go will not support setting an API object timestamp returned via GetCreationTimestamp. This causes errant behavior in UpdatingObjectManager.Manage as a non-zero creation timestamp is used to indicate various states.

Of course I could test it differently. Looking through the lens of community adoption though, it becomes more difficult to "drop in" the library as a prototype and have existing unit tests show equivalent behavior.

Curious how this issue strikes others. I think upstream is wrong, that there should be some means of some pluggable behavior, but there's practically no traction on the issue in client-go for years.

EDIT: also see #589

[scothis]

Hi @briantopping.

Inside our TestClient we default the creation date when adding given resources. This is the client that is configured automatically when used by the testing support.

runtime/testing/client.go

Lines 96 to 98 in d175b3a

	if obj.GetCreationTimestamp().Time.IsZero() {
	obj.SetCreationTimestamp(metav1.NewTime(time.UnixMilli(1000)))
	}

It sounds like you're trying to reuse an existing test harness with an RIO reconciler. Can you describe/share how you're trying to drive the tests? There's probably a way to set/default the creation date for the resource.

[briantopping]

Hi @scothis, thanks for this info. You are correct that this is with functionally the same test harness that is generated by Kubebuilder, using EnvTest. The demo I am trying to create would show the benefits of RIO with least changes to make it attractive to other team members.

Now that I understand more about what's going on with your help. I was able to reuse TestClient from reconciler.io/runtime/testing. I tried it with AddGiven and AddReactor. The latter only allows access to the objectMeta when the Action is a CreateAction. Ideally, the reactor would allow for tail patching a Get call, but I don't see how that's possible. As mentioned, I have tried to push an explicit date in the client.Create call, and the creation time is zeroed out.

I need to find exactly where, but it seems the problem is in the client provided by EnvTest. With no way I can see to tail patch the call to Get, there isn't much way to force a non-zero CreationTimestamp.

I'd understand if this is out-of-scope to resolve, please close out the issue if so. This concept of introducing RIO to existing operators does seem like a logical adoption path though. Kubebuilder is a popular way to get started building controllers. It could be great to have a recipe (blog post etc) that walked through the conversion.