added fetcher test cases

[vardhaman-surana]

Description

Which issue(s) this PR fixes:

Fixes #

Testing

Checklist:

• I ran tests as well as code linting locally to verify my changes.
• I have done manual verification of my changes, changes working as expected.
• I have added new tests to cover my changes.
• My changes follow contributing guidelines of Fission.
• I have signed all of my commits.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (9b57f1f) 44.24% compared to head (db62c26) 46.68%.
Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2893      +/-   ##
==========================================
+ Coverage   44.24%   46.68%   +2.43%     
==========================================
  Files         213      215       +2     
  Lines       22465    22551      +86     
==========================================
+ Hits         9939    10527     +588     
+ Misses      11260    10668     -592     
- Partials     1266     1356      +90     

Flag	Coverage Δ
unittests	46.68% <100.00%> (+2.43%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.