Handling Errors in Async Tests
test.js
Testing asynchronous code often means checking not only for successful outcomes, but also for correct error handling. In Jest, you can use expect().resolves to check that a promise resolves as expected, and expect().rejects to check that a promise rejects. When you want to ensure an async function throws or rejects with a specific error, you should use expect().rejects.toThrow(errorMessage).
In the code above, the fetchData function either resolves with "Success!" or throws an error, depending on the input. The first test uses resolves.toBe to confirm a successful result, while the second test uses rejects.toThrow to assert that the error is thrown as expected. This approach allows you to verify that your code handles errors properly in asynchronous scenarios, making your tests more robust and reliable.
1. How can you check if an async function throws or rejects in Jest?
2. Why is it important to test error handling in asynchronous code?
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test.js
Testing asynchronous code often means checking not only for successful outcomes, but also for correct error handling. In Jest, you can use expect().resolves to check that a promise resolves as expected, and expect().rejects to check that a promise rejects. When you want to ensure an async function throws or rejects with a specific error, you should use expect().rejects.toThrow(errorMessage).
In the code above, the fetchData function either resolves with "Success!" or throws an error, depending on the input. The first test uses resolves.toBe to confirm a successful result, while the second test uses rejects.toThrow to assert that the error is thrown as expected. This approach allows you to verify that your code handles errors properly in asynchronous scenarios, making your tests more robust and reliable.
1. How can you check if an async function throws or rejects in Jest?
2. Why is it important to test error handling in asynchronous code?
Tack för dina kommentarer!
