Add jest tests for React components

[alexjball]

Add a Jest test to Main.test.tsx that renders the Main component, fills out the transition form, and renders the results table using the FakeApi. This tests interactions with the form and the container logic. Use react testing library and user-event to render and interact with the page. Here is an example of a Jest test that renders and fills out another form.

[edward-malouf]

Attached is the screen layout for an 1152 x 700 laptop.
JobHopper Design 2020 10-13.pdf

[jedpittman]

@russ430 can you please provide a pull request with any work that you've done on this? If not, please reach out to me or @alexjball so that we can reassign the work.

[russ430]

@jedpittman I believe @alexjball is working on finalizing some of the components that we'll be adding the jest tests to, I don't think they're completely ready just yet to start testing.