Add new test case for force-leave

[dttung2905]

Hi team,

This MR aims to add the test case for force-leave on exsisting node

It will solve issue #15559

[tgross]

Thanks for this PR @dttung2905!

[tgross]

For this kind of thing, rather than waiting a static period of time, we can use shoenig/test/wait to wait until the assertion is true or the timeout expires. That lets us move the test along if the desired state is reached quickly.

For example, the following takes <3sec on my machine instead of >6sec. This adds up given the number of tests we run!

Suggested change

	time.Sleep(3 * time.Second)
	membersAfter, err := a.MembersOpts(&QueryOptions{})
	for _, node := range membersAfter.Members {
	if node.Name == membersBefore.Members[1].Name {
	must.Eq(t, node.Status, "leaving")
	}
	}
	f := func() error {
	membersAfter, err := a.MembersOpts(&QueryOptions{})
	if err != nil {
	return err
	}
	for _, node := range membersAfter.Members {
	if node.Name == membersBefore.Members[1].Name {
	if node.Status != "leaving" {
	return fmt.Errorf("node did not leave")
	}
	}
	}
	return nil
	}
	must.Wait(t, wait.InitialSuccess(
	wait.ErrorFunc(f),
	wait.Timeout(3*time.Second),
	wait.Gap(100*time.Millisecond),
	))

[dttung2905]

Thanks alot for the suggestion and the code snippet. This is exactly what I'm looking for when writing this test. Totally agree that we can greatly reduce the test run time by making the wait.Gap() more aggressive instead of waiting for the whole duration.

[tgross]

LGTM! Thanks again @dttung2905!