I am testing an endpoint with JEST and Got. I expect 403 Forbidden error. The following code prints the error from catch block AND fails that the identical call does not throw an error. Why?
try {
response = await api(`verify/${profile.auth.verifyToken}`, {method: 'POST'}).json();
} catch (e) {
console.log(e);
}
expect(async () => {
response = await api(`verify/${profile.auth.verifyToken}`, {method: 'POST'}).json();
}).toThrow();
Output:
console.log test/api.int.test.js:112
HTTPError: Response code 403 (Forbidden)
at EventEmitter.<anonymous> (C:\dev\mezinamiridici\infrastructure\node_modules\got\dist\source\as-promise.js:118:31)
at processTicksAndRejections (internal/process/task_queues.js:97:5) {
name: 'HTTPError'
}
Error: expect(received).toThrow()
Received function did not throw
This variant does not work either:
expect(() => api(`verify/${profile.auth.verifyToken}`, {method: 'POST'})).toThrow();
Btw when the HTTPError is thrown and not catched, there is no stacktrace and I do not see where the error was thrown. If there are other error I exactly see which test line was responsible. Why?
expect(...).toThrow()
is for checking if an error is thrown from a function call. When calling an async function, it never throws an error; rather it returns a Promise
which may eventually become "rejected." Although async functions use the same throw
/catch
terminology, the code required to detect a thrown error differs from what's required to detect a rejected Promise. This is why Jest needs a different assertion technique.
Try expect(...).rejects.toThrow()
instead:
await expect(api(`verify/${profile.auth.verifyToken}`, {method: 'POST'}).json())
.rejects.toThrow();
Notice you have to await
this assertion because Jest needs to wait until the Promise
finalizes before seeing whether it resolved or rejected.