Jest Multi Project Nextjs myTest.spec.tsx (frontend test, jsdom), anotherTest.server.tsx (backend test, node)

jest.config.js

module.exports = {
  projects: [
    '<rootDir>/jest.frontend.config.js',
    '<rootDir>/jest.server.config.js',
  ],
}

jest.frontend.config.js

const nextJest = require('next/jest')

const createJestConfig = nextJest({
  // Provide the path to your Next.js app to load next.config.js and .env files in your test environment
  dir: './',
})

// Add any custom config to be passed to Jest
const customJestConfig = {
  testRegex: '((\\.|/)(spec))\\.(js|ts|tsx)?$',
  setupFilesAfterEnv: ['<rootDir>/jest.setup.js'],
  setupFiles: ['<rootDir>/test/setupFiles.js'],
  moduleNameMapper: {
    // Handle module aliases (this will be automatically configured for you soon)
    '^@/components/(.*)$': '<rootDir>/components/$1',
    '^@/pages/(.*)$': '<rootDir>/pages/$1',
  },
  testEnvironment: 'jsdom',
}

// createJestConfig is exported this way to ensure that next/jest can load the Next.js config which is async
module.exports = createJestConfig(customJestConfig)

jest.server.config.js

const nextJest = require('next/jest')

const createJestConfig = nextJest({
  // Provide the path to your Next.js app to load next.config.js and .env files in your test environment
  // dir: './',
})

// Add any custom config to be passed to Jest
const customJestConfig = {
  preset: '@shelf/jest-mongodb',
  testRegex: '((\\.|/)(server))\\.(js|ts|tsx)?$',
  setupFiles: ['<rootDir>/test/setupFiles.js'],
  setupFilesAfterEnv: ['<rootDir>/jest.server.setup.js'],
}

// createJestConfig is exported this way to ensure that next/jest can load the Next.js config which is async
module.exports = createJestConfig(customJestConfig)