Sometimes, we want to make a mock throw an error in Jest.
In this article, we’ll look at how to make a mock throw an error in Jest.
How to make a mock throw an error in Jest?
To make a mock throw an error in Jest, we can call mockImplementation with a function that throws an error.
For instance, we write:
yourMockInstance.mockImplementation(() => {
throw new Error();
});
to use throw to thrown an error in the mocked implementation of yourMockInstance.
If we’re mocking async functions, we can use mockRejectedValue to mock the value of a rejected promise returned by the async function.
For instance, we write
test('async test', async () => {
const yourMockFn = jest.fn().mockRejectedValue(new Error('Async error'));
await yourMockFn();
});
then we should see 'Async error' as the promise rejection message when we call yourMockFn.
Conclusion
To make a mock throw an error in Jest, we can call mockImplementation with a function that throws an error.
