Added unit tests for snapshot in pkg/util/lifted/scheduler/cache

[yashpandey06]

What type of PR is this?

/kind feature

Description:

This PR adds unit tests for the Snapshot functionality in the cache package.

Key Changes:

• Added tests for NewEmptySnapshot, NewSnapshot, and various Snapshot methods like Get, List, and IsPVCUsedByPods.
• Tests cover scenarios like empty snapshots, node and PVC tracking, and error handling for non-existent nodes.
  Fixes part of [lfx-mentorship-2024-September-November] Enhance Karmada controller-manager and schedule testing coverage #5235

Does this PR introduce a user-facing change?:

NONE

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Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 30.90%. Comparing base (2537912) to head (ae26bfe).

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Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5424      +/-   ##
==========================================
- Coverage   31.05%   30.90%   -0.16%     
==========================================
  Files         639      639              
  Lines       44313    44313              
==========================================
- Hits        13763    13696      -67     
- Misses      29556    29642      +86     
+ Partials      994      975      -19     

Flag	Coverage Δ
unittests	30.90% <ø> (-0.16%)	⬇️

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[XiShanYongYe-Chang]

/assign

[karmada-bot]

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[yashpandey06]

@XiShanYongYe-Chang please help review this pr , i have already fixed the headers data

[XiShanYongYe-Chang]

Hi @yashpandey06 Is the following test code copied directly from this file? I looked at it and it doesn't seem to be directly copied. You can copy the test functions from the https://github.com/kubernetes/kubernetes/blob/release-1.26/pkg/scheduler/internal/cache/snapshot_test.go file without having to add the test code yourself.

[yashpandey06]

Thanks for the review , I am working on it.