jest.config.js

// For a detailed explanation regarding each configuration property, visit:
// https://jestjs.io/docs/en/configuration.html

module.exports = {
  // Automatically clear mock calls and instances between every test
  clearMocks: true,

  // An array of glob patterns indicating a set of files for which coverage information should be collected
  collectCoverageFrom: [
    'src/js/*.js',
    'src/js/*.svelte',
    'src/js/components/**/*.svelte',
    'src/js/utils/*.js',
    'src/js/utils/*.svelte'
  ],

  // The directory where Jest should output its coverage files
  coverageDirectory: 'coverage',

  // An array of file extensions your modules use
  moduleFileExtensions: ['js', 'svelte'],

  // The root directory that Jest should scan for tests and modules within
  rootDir: './',

  // A list of paths to directories that Jest should use to search for files in
  roots: [
    '<rootDir>/test/unit'
  ],

  // The path to a module that runs some code to configure or set up the testing framework before each test
  setupFilesAfterEnv: ['<rootDir>/test/unit/setupTests.js'],

  // A map from regular expressions to paths to transformers
  transform: {
    '^.+\\.js$': 'babel-jest',
    '^.+\\.svelte$': ['svelte-jester', {
      preprocess: true,
      compilerOptions: {
        dev: false
      }
    }],
    '.+\\.(css|styl|less|sass|scss)$': 'jest-transform-css'
  }
};