Create Unit tests for the frontend

[leticiaarj]

Perform unit tests on the frontend project, having code coverage and possible error analysis.

Tasks

• [ ] Test as many components and methods as possible.
• [ ] Check the return of each test and signal the team about possible errors.
• [ ] Run the tests using the instructions contained here: https://github.com/lappis-unb/BotFlow.

Acceptance criteria

• [ ] The tests are working.
• [ ] The project is running.

[leticiaarj]

Derived from the issue #146.