Add unit testing for React components using Jest

[singh-sarabjeet]

Is your feature request related to a problem? Please describe.
A unit testing framework will ensure the code doesn't break by additions of new features or bug fixes.

Describe the solution you'd like
We can add Jest as the testing library and all new features added should have unit test cases for them. Also, unit test cases for previously written code can be added slowly.

Describe alternatives you've considered
Multiple alternatives such as Mocha, Jasmine, Enzyme and React-testing-library were considered but Jest is the recommended library for testing react by Facebook.