Inside both directories, you can run (on UI you could use Yarn too):
On UI: Runs the app in the development mode. Open http://localhost:3001 to view it in the browser. The page will reload if you make edits.
On Server: Starts the app on port 3000 by default.
On UI: Launches the test runner in the interactive watch mode. Powered by Jest and Enzyme.
On Server: Runs the tests (under the tests folder), it uses Jest and SuperTest.
Same as npm run test but it always run all the available tests and evaluates the test coverage. A convenient HTML report is generated under the coverage folder.
For this project we have a mandatory 100% code coverage, otherwise this will fail.