string token to include the path to your project's root directory to prevent it from accidentally ignoring all of your files in different environments that may have different root directories. Use the string token to include the path to your project's root directory to prevent it from accidentally ignoring all of your files in different environments that may have different root directories. (module1-utils.js) In the other module, we will test for positive, negative, and sum of the values. Notifications will be properly displayed on subsequent runs. It is possible to override this setting in individual tests by explicitly calling jest.mock() at the top of the test file. Tests are parallelized by running them in their own processes to maximize performance. Note: Core modules, like fs, are not mocked by default.