Removed test script and used jest directly instead

scripts/test.js

@@ -1,19 +0,0 @@
-// Do this as the first thing so that any code reading it knows the right env.
-process.env.BABEL_ENV = 'test';
-process.env.NODE_ENV = 'test';
-process.env.PUBLIC_URL = '';
-
-// Makes the script crash on unhandled rejections instead of silently
-// ignoring them. In the future, promise rejections that are not handled will
-// terminate the Node.js process with a non-zero exit code.
-process.on('unhandledRejection', (err) => {
-  throw err;
-});
-
-// Make tests to be matched inside tests folder
-const jest = require('jest');
-
-const argumentsToRemove = 2;
-const argv = process.argv.slice(argumentsToRemove);
-
-jest.run(argv);