Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.
feat(fakeclient): push event on watched channel on add/update/delete
**What this PR does / why we need it**:
This PR enables watch function for kubernetes [fakeclient](1bcf0b0a22/staging/src/k8s.io/client-go/kubernetes/fake/clientset_generated.go (L88)).
This fake client add watchReactorFunction by wrapping [watch.NewFake](1bcf0b0a22/staging/src/k8s.io/client-go/kubernetes/fake/clientset_generated.go (L98)) which is a `chan Event` but actually nothing pushes objects into this channel. So all watch function called by fake client will never return or never receive any object.
This PR intercepts ReactionFunc of `Create / Update / DeleteActionImpl` and will push the requested object to channel.
Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes#54075
**Special notes for your reviewer**:
**Release note**:
```dev-release-note
enable watch function for fake client
```
Automatic merge from submit-queue
Track object modifications in fake clientset
Fake clientset is used by unit tests extensively but it has some
shortcomings:
- no filtering on namespace and name: tests that want to test objects in
multiple namespaces end up getting all objects from this clientset,
as it doesn't perform any filtering based on name and namespace;
- updates and deletes don't modify the clientset state, so some tests
can get unexpected results if they modify/delete objects using the
clientset;
- it's possible to insert multiple objects with the same
kind/name/namespace, this leads to confusing behavior, as retrieval is
based on the insertion order, but anchors on the last added object as
long as no more objects are added.
This change changes core.ObjectRetriever implementation to track object
adds, updates and deletes.
Some unit tests were depending on the previous (and somewhat incorrect)
behavior. These are fixed in the following few commits.
