Two separate environments exist for this challenge. The test environment, which is remotely executed within a NodeJS runtime, and the web preview environment, which is bundled using Webpack. The package.json does not control both environments.
The code for this project is tested using Node 18, with Jest as the test framework. JSX is supported, as well as ES6 style imports. The code is executed in a remote environment, not within your browser. Any console.log statements executed while running tests will not send logs to your browser, but the output will be shown at the bottom of your tests. Jest does not support inline console.log statements. This is why logs come after all test output.
Any package that is already loaded into the runner environment is able to be used; there is no package.json file that manages what is executed within tests.
Stylesheets and other assets can be imported. See jest.config.js and the mocks directory to see what is loaded in their place. By default, these imports have no impact on tests, only the web preview environment.
Web Preview Environment The web preview environment uses Sandpack to bundle assets. The package.json file is used to determine what gets loaded into this environment. There are no special config files; everything is inferred from package.json.
Customization is possible, but be careful not to use different versions within the web preview environment than what is loaded within the test environment. In some cases you can load additional dependencies if it is only cosmetic (styling) or meant for building preview assets, but those dependencies may not be available within the runner environment and can cause issues with your tests.