Jest
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Setup and Teardown

Setup and Teardown

Often while writing tests you have some setup work that needs to happen before tests run, and you have some finishing work that needs to happen after tests run. Jest provides helper functions to handle this.

Repeating Setup For Many Tests

If you have some work you need to do repeatedly for many tests, you can use beforeEach and afterEach.

For example, let's say that several tests interact with a database of cities. You have a method initializeCityDatabase() that must be called before each of these tests, and a method clearCityDatabase() that must be called after each of these tests. You can do this with:

beforeEach(() => {
  initializeCityDatabase();
});

afterEach(() => {
  clearCityDatabase();
});

test('city database has Vienna', () => {
  expect(is