Arrange in unit test

• Preparing to acting of tests
  • All errors in this phase are not actually errors / failures of tests
  • In terms of JestJS, most likely, beforeEach or beforeAll methods
  • Sometimes we need to mock import/require (in JavaScript)
    • It can be done by means of framework like JestJS
    • It can be done by means of independent library like Rewire
  • Here you should write stubs, mocks, etc (Test Doubles)