Add Test cases for frontend using Jest and Enzyme.

[rupav]

This issue is to achieve 100% code coverage on frontend.

Cheklist:

• Add JEST - refer Add jest testing framework #45
• Add coverage tool - refer Add jest coverage configuration. #49
• Add enzyme. - Update: 11th June: Well using enzyme is not going to work because of no official support to Preact. Might be removed in upcoming PRs.
• Complete actions test
• Complete Reducers test
• Complete Components test