Jest: Shared Async Code Between Test Blocks

I have some test code like this: test('Test', async () => { const someData = await setup() const actual = myFunc(someData.x) expect(actual.a).toEqual(someData.y) expect(

Solution 1:

It's correct that describe callback function isn't supposed to be asynchronous. It synchronously defines tests for a suite, any asynchronous operations in its scope will be discarded.

Previously Jasmine and Jest allowed to access common test context with regular functions and this. This feature was deprecated in Jest; common variables need to be user-defined.

Shared code can be moved into helper function that internally uses beforeAll, beforeEach, etc:

constsetupWithTestContext = (testContext = {}) => {
  beforeAll(async () => {
    const setupData = awaitsetup();
    Object.assign(testContext, setupData);
  });
  return testContext; // sets up a new one or returns an existing
});

constanotherSetupWithTestContext = (testContext = {}) => {
  beforeEach(() => {
    testContext.foo = 0;
  });
  return testContext;
});

...

describe('Some group of tests', async () => {
    const sharedTestData = setupTestContext();
    // or// const sharedTestData = {}; setupTestContext(sharedTestData);anotherSetupWithTestContext(sharedTestData);

    test('Test1', async () => {
      // context is filled with data at this pointconst actual = myFunc(sharedTestData.x)
      ...
    }
    ...
})