jest.config.js

module.exports = {
    collectCoverage: true,
    // on node 14.x coverage provider v8 offers good speed and more or less good report
    coverageProvider: 'v8',
    collectCoverageFrom: [
        '**/*.{js,jsx,ts,tsx}',
        '!**/*.d.ts',
        '!**/node_modules/**',
        '!<rootDir>/out/**',
        '!<rootDir>/.next/**',
        '!<rootDir>/*.config.js',
        '!<rootDir>/coverage/**',
    ],
    moduleNameMapper: {
        // Handle CSS imports (with CSS modules)
        // https://jestjs.io/docs/webpack#mocking-css-modules
        '^.+\\.module\\.(css|sass|scss)$': 'identity-obj-proxy',

        // Handle CSS imports (without CSS modules)
        '^.+\\.(css|sass|scss)$': '<rootDir>/__mocks__/styleMock.js',

        // Handle image imports
        // https://jestjs.io/docs/webpack#handling-static-assets
        '\\.(jpg|jpeg|png|gif|eot|otf|webp|svg|ttf|woff|woff2|mp4|webm|wav|mp3|m4a|aac|oga)$':
            '<rootDir>/__mocks__/fileMock.js',
        '\\.(css|less)$': '<rootDir>/__mocks__/styleMock.js',

        // Handle module aliases
        '^@/components/(.*)$': '<rootDir>/components/$1',
    },
    // Add more setup options before each test is run
    // setupFilesAfterEnv: ['<rootDir>/jest.setup.js'],
    testPathIgnorePatterns: ['<rootDir>/node_modules/', '<rootDir>/.next/'],
    testEnvironment: 'jsdom',
    transform: {
        // Use babel-jest to transpile tests with the next/babel preset
        // https://jestjs.io/docs/configuration#transform-objectstring-pathtotransformer--pathtotransformer-object
        '^.+\\.(js|jsx|ts|tsx)$': ['babel-jest', { presets: ['next/babel'] }],
    },
    transformIgnorePatterns: [
        '/node_modules/',
        '^.+\\.module\\.(css|sass|scss)$',
    ],
    setupFilesAfterEnv: [
        "@testing-library/jest-dom/extend-expect",
        "<rootDir>/setupTests.js",
    ]
}