awaitexpect(user.getUserName(1)).rejects.toThrow('User with 1 not found.');
});
```
You can also work with Promise chains. In this case, you can make use of the `done` callback and `done.fail` in case an error occurred. Following are some examples:
You can also simply return a promise from the test function.
NOTE: **Note:**
Using the `done` and `done.fail` callbacks is discouraged when working with
promises. They should only be used when testing callback-based code.
**Bad**:
```javascript
// missing done callback
// missing return
it('tests a promise',()=>{
promise.then(data=>{
expect(data).toBe(asExpected);
});
});
// missing catch
it('tests a promise',done=>{
promise
.then(data=>{
expect(data).toBe(asExpected);
})
.then(done);
});
// use done.fail in asynchronous tests
// uses done/done.fail
it('tests a promise',done=>{
promise
.then(data=>{
expect(data).toBe(asExpected);
})
.then(done)
.catch(fail);
});
// missing catch
it('tests a promise rejection',done=>{
promise
.catch(error=>{
expect(error).toBe(expectedError);
})
.then(done);
.catch(done.fail);
});
```
**Good**:
```javascript
// handling success
it('tests a promise',done=>{
promise
// verifying a resolved promise
it('tests a promise',()=>{
returnpromise
.then(data=>{
expect(data).toBe(asExpected);
})
.then(done)
.catch(done.fail);
});
});
// failure case
it('tests a promise rejection',done=>{
promise
.then(done.fail)
.catch(error=>{
expect(error).toBe(expectedError);
})
.then(done)
.catch(done.fail);
// verifying a resolved promise using Jest's `resolves` matcher
it('tests a promise',()=>{
returnexpect(promise).resolves.toBe(asExpected);
});
// verifying a rejected promise using Jest's `rejects` matcher
