Fixes #764: Add new test for reg-exp utility to increase test coverage

[simsausaurabh]

Changes proposed in this pull request

• Added new test case file for reg-exp utility function.
• 13 new test units are added. Now total test units are: 170+13 = 183.

Screenshots (if appropriate)

Link to live demo: http://pr-765-fossasia-loklaksearch.surge.sh

Closes #764

[codecov]

Codecov Report

Merging #765 into development will increase coverage by 0.04%.
The diff coverage is n/a.

@@              Coverage Diff               @@
##           development    #765      +/-   ##
==============================================
+ Coverage        51.66%   51.7%   +0.04%     
==============================================
  Files               99      99              
  Lines             2499    2499              
  Branches           278     278              
==============================================
+ Hits              1291    1292       +1     
  Misses            1180    1180              
+ Partials            28      27       -1

Impacted Files	Coverage Δ
src/app/lazy-img/lazy-img.service.ts	64.44% <0%> (+2.22%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 59c45b7...0da2cbb. Read the comment docs.

[simsausaurabh]

@praveenojha33 @singhpratyush Please review.

[praveenojha33]

LGTM 👍