[good first issue]add relative unit testcase for merged PRs

[lowang-bh]

What would you like to be added:

Add UT to cover the pod's condition message in allocate/preempt/reclaim/backfill action, according to relative issues and PRs as following.

• allocate
  • Issue:
    • failed to be scheduled pod's message increased explosively with large number of nodes #3049,
    • predicate does not stop if node is not suitable for current pod  #3050
  • PR: fix: schedule message burst with nodes number increasion #3051
• preempt
  • Issue
    • Preemption conflicts with the anti-affinity #3068
    • The number of node pods has reached the upper limit and cannot be preempted #3079
  • PR Fix the conflict between preemption and antiAffinity #3070
• reclaim
• backfill

Why is this needed:

To prevent future changes cause new issue and breaking current fix.
The origin idea is from issue #3049

[lowang-bh]

/good-first-issue

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[MondayCha]

Hello, I am hoping to start with this good first issue on Volcano. Could it be assigned to me?

[lowang-bh]

/assign @MondayCha

[JesseStutler]

@MondayCha Hi, do you still work on this? Could you assign to me? I'm ready to add some UTs to start at volcano.

[lowang-bh]

/assign @JesseStutler

[JesseStutler]

I think the current testing framework's scalability is a bit poor...Like I want to add UT in reclaim action, I want to build a pod with preemptionPolicy with pod, I need to add a function based on BuildPod, but now the parameter list of BuildPod is a bit too long:

volcano/pkg/scheduler/util/test_utils.go

Line 57 in 0843c0d

func BuildPod(namespace, name, nodeName string, p v1.PodPhase, req v1.ResourceList, groupName string, labels map[string]string, selector map[string]string) *v1.Pod {

I don’t know what the parameters in which position are used for. On the contrary, the way of writing in the k8s repository is clearer:
https://github.com/kubernetes/kubernetes/blob/master/pkg/controller/job/job_controller_test.go#L7791-L7827

It is better to expand the fields in this way. Now it is difficult for BuildPod to expand the fields, parameter list will be longer and longer...