Add channel metadata conformance tests

[aliok]

Fixes #1960

Proposed Changes

Implements channel metadata conformance tests. There are 3 tests described in the issue #1960.

1. Checking if the channel CRD is namespaced (and not cluster scoped)
2. Checking if the channel CRD has the labels messaging.knative.dev/subscribable=true and duck.knative.dev/addressable=true
3. Checking if the channel CRD has the category channel

1 and 3 is done by checking the ApiResource.
For 2, I had to actually get the CRD and check if it has the label.

Release Note

NONE

How to run the added tests?

go test -v -timeout 30s -tags e2e knative.dev/eventing/test/conformance -run ^TestChannelCRDMetadata$ -channels messaging.knative.dev/v1alpha1:InMemoryChannel,messaging.knative.dev/v1alpha1:Channel,messaging.knative.dev/v1beta1:InMemoryChannel

[mattmoor]

Produced via:
gofmt -s -w $(find -path './vendor' -prune -o -path './third_party' -prune -o -type f -name '*.go' -print)

[aliok]

/retest

[aliok]

Not sure why this fails.

Doing the following works locally for me on my Minikube:

go test -v -timeout 30s -tags e2e knative.dev/eventing/test/conformance -run ^TestChannelCRDMetadata$ -channels messaging.knative.dev/v1alpha1:InMemoryChannel,messaging.knative.dev/v1alpha1:Channel,messaging.knative.dev/v1beta1:InMemoryChannel

[aliok]

The test is unable to get the CRDs. It cannot list as well.
I did a small experiment here: #2965, specifically https://github.com/knative/eventing/pull/2965/files?file-filters%5B%5D=.go&file-filters%5B%5D=.sh&hide-deleted-files=true#diff-b48ad686db0c8498a33308be0d585ac4R50 .
Prow line: https://prow.knative.dev/view/gcs/knative-prow/pr-logs/pull/knative_eventing/2965/pull-knative-eventing-integration-tests/1249094584215015425#1:build-log.txt%3A496

The call client.Apiextensions.CustomResourceDefinitions().List(metav1.ListOptions{}) returns the server could not find the requested resource. A Get call returns the same too.

I think the service account that is used to run the tests should be updated to have at least get verb to CRDs. No idea who to ping for this.
Why this is needed is in the PR description.

[aliok]

cc @chaodaiG @n3wscott
TLDR; can we give get verb permissions for apiextensions.k8s.io CustomResourceDefinition to the service account that's running the tests on Prow?

[chaodaiG]

@chizhg is oncall this week, please investigate what's needed to make it work

[aliok]

@chizhg

get and list permissions for apiextensions.k8s.io CustomResourceDefinition is needed at the service account that's running the tests on Prow.
I spent some time in knative/test-infra but couldn't figure it out myself.

[aliok]

I found the problem. apiextensions is v1beta1 in GKE, not v1.

I was checking the wrong things around RBAC, service accounts, permissions etc. the whole time 🤦‍♂️

sorry for misleading you and thanks for your help

all is green now.

[matzew]

/lgtm
/approve

[knative-prow-robot]

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[aliok]

ping @pierDipi
if you want to do something similar to knative/eventing-contrib#1154 with these tests

[pierDipi]

@aliok sure, I will let you know when it's ready.