feat(backup): add unit tests for backup module

[xxo1shine]

What does this PR do?
Add new unit tests for the backup module.

Why are these changes required?

This PR has been tested by:

• Unit Tests
• Manual Testing

Follow up

Extra details

[codecov-commenter]

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Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 55.96%. Comparing base (54c05e5) to head (bc2c141).
Report is 170 commits behind head on release_v4.7.2.

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Additional details and impacted files

@@                 Coverage Diff                  @@
##             release_v4.7.2    #5158      +/-   ##
====================================================
+ Coverage             55.82%   55.96%   +0.13%     
- Complexity             8358     8389      +31     
====================================================
  Files                   836      836              
  Lines                 49592    49592              
  Branches               5517     5517              
====================================================
+ Hits                  27683    27752      +69     
+ Misses                19691    19619      -72     
- Partials               2218     2221       +3     

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