Использование синтаксиса async/await:

test('example test', async () => {
 const response = await fetch('https://api.example.com/data');
 const data = await response.json();
 expect(data).toEqual(/* expected value */);
});

Использование обещаний:

test('example test', () => {
 return fetch('https://api.example.com/data')
   .then(response => response.json())
   .then(data => {
     expect(data).toEqual(/* expected value */);
   });
});

Использование asyncи done:

test('example test', (done) => {
 fetch('https://api.example.com/data')
   .then(response => response.json())
   .then(data => {
     expect(data).toEqual(/* expected value */);
     done();
   })
   .catch(error => {
     done.fail(error);
   });
});

Использование async/awaitс resolves:

test('example test', async () => {
 await expect(fetch('https://api.example.com/data')).resolves.toEqual(/* expected value */);
});

Использование async/awaitс rejects:

test('example test', async () => {
 await expect(fetch('https://api.example.com/data')).rejects.toThrow(/* expected error */);
});