KEP-2133: Update test plan

Signed-off-by: ruiwen-zhao <ruiwen@google.com>

keps/sig-node/2133-kubelet-credential-providers/README.md

@@ -15,6 +15,10 @@
     - [Caching Credentials](#caching-credentials)
   - [Metrics](#metrics)
   - [Test Plan](#test-plan)
+      - [Prerequisite testing updates](#prerequisite-testing-updates)
+      - [Unit tests](#unit-tests)
+      - [Integration tests](#integration-tests)
+      - [e2e tests](#e2e-tests)
   - [Graduation Criteria](#graduation-criteria)
   - [Alpha](#alpha)
     - [Alpha -> Beta Graduation](#alpha---beta-graduation)
@@ -333,6 +337,70 @@ Beta:
 GA:
 * e2e test with an external implementation (e.g. [GCR](https://github.com/kubernetes/cloud-provider-gcp/tree/master/cmd/auth-provider-gcp)).
 
+[X] I/we understand the owners of the involved components may require updates to
+existing tests to make this code solid enough prior to committing the changes necessary
+to implement this enhancement.
+
+##### Prerequisite testing updates
+
+<!--
+Based on reviewers feedback describe what additional tests need to be added prior
+implementing this enhancement to ensure the enhancements have also solid foundations.
+-->
+
+N/A
+
+##### Unit tests
+
+<!--
+In principle every added code should have complete unit test coverage, so providing
+the exact set of tests will not bring additional value.
+However, if complete unit test coverage is not possible, explain the reason of it
+together with explanation why this is acceptable.
+-->
+
+<!--
+Additionally, for Alpha try to enumerate the core package you will be touching
+to implement this enhancement and provide the current unit coverage for those
+in the form of:
+- <package>: <date> - <current test coverage>
+The data can be easily read from:
+https://testgrid.k8s.io/sig-testing-canaries#ci-kubernetes-coverage-unit
+This can inform certain test coverage improvements that we want to do before
+extending the production code to implement this enhancement.
+-->
+
+The unit test coverage is in k8s.io/kubernetes/pkg/credentialprovider package:
+
+- k8s.io/kubernetes/pkg/credentialprovider: 06/21/2022 - 47.2
+
+##### Integration tests
+
+<!--
+This question should be filled when targeting a release.
+For Alpha, describe what tests will be added to ensure proper quality of the enhancement.
+For Beta and GA, add links to added tests together with links to k8s-triage for those tests:
+https://storage.googleapis.com/k8s-triage/index.html
+-->
+
+Please see below under e2e tests.
+
+##### e2e tests
+
+<!--
+This question should be filled when targeting a release.
+For Alpha, describe what tests will be added to ensure proper quality of the enhancement.
+For Beta and GA, add links to added tests together with links to k8s-triage for those tests:
+https://storage.googleapis.com/k8s-triage/index.html
+We expect no non-infra related flakes in the last month as a GA graduation criteria.
+-->
+
+An e2e test using a mock credential provider has been added for Beta launch:
+
+- test/e2e_node/image_credential_provider.go: https://testgrid.k8s.io/sig-node-kubelet#kubelet-credential-provider
+
+For GA launch, we will add an e2e test that utilizes the GCP credential provider (https://github.com/kubernetes/cloud-provider-gcp).
+
 ### Graduation Criteria
 
 ### Alpha

keps/sig-node/2133-kubelet-credential-providers/kep.yaml

@@ -23,7 +23,7 @@ replaces:
   - "/keps/sig-cloud-provider/20191004-out-of-tree-credential-providers.md"
 
 # The target maturity stage in the current dev cycle for this KEP.
-stage: beta
+stage: stable
 
 # The most recent milestone for which work toward delivery of this KEP has been
 # done. This can be the current (upcoming) milestone, if it is being actively