[test] : add unittests for node_controller

[rahulait]

This PR adds unittests for node_controller.go file

General:

• Have you removed all sensitive information, including but not limited to access keys and passwords?
• Have you checked to ensure there aren't other open or closed Pull Requests for the same bug/feature/question?

Pull Request Guidelines:

1. Does your submission pass tests?
2. Have you added tests?
3. Are you addressing a single feature in this PR?
4. Are your commits atomic, addressing one change per commit?
5. Are you following the conventions of the language?
6. Have you saved your large formatting changes for a different PR, so we can focus on your work?
7. Have you explained your rationale for why this feature is needed?
8. Have you linked your PR to an open issue

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 62.48%. Comparing base (b1b9af7) to head (0d2db68).
Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #284      +/-   ##
==========================================
+ Coverage   57.92%   62.48%   +4.55%     
==========================================
  Files          12       12              
  Lines        2415     2415              
==========================================
+ Hits         1399     1509     +110     
+ Misses        864      755     -109     
+ Partials      152      151       -1     

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