How to test an exception was not thrown with Jest?

Question

The Jest docs do not demonstrate a way of asserting that no exception was thrown, only that one was.

expect(() => ...error...).toThrow(error)

How do I assert if one was not thrown?

If you have an uncaught exception, your tests will fail. Is there a situation where many different type of exceptions can be thrown except one type? — Balázs Édes, Apr 01 '18 at 22:53

score 121 · Accepted Answer · edited Mar 22 '22 at 15:44

121

You can always use the .not method, which will be valid if your initial condition is false. It works for every jest test:

expect(() => ...error...).not.toThrow(error)

edited Mar 22 '22 at 15:44

agilgur5

answered Apr 01 '18 at 22:49

Axnyff

1

I'm wondering if this can handle functions with void return type? I'm getting `Error: expect(received).not.toThrowError() \n Matcher error: received value must be a function \n Received has value: undefined` – Bence Szalai May 06 '22 at 21:38
3

@sbnc.eu It works also for void return type if you wrap it into a function. `expect(() => myvoidreturnfunction()).not.toThrow()` – LiMuBei May 30 '22 at 14:44

Camilo · Answer 2 · 2022-04-26T18:47:33.320

29

In my case the function being tested was asynchronous and I needed to do further testing after calling it, so I ended up with this:

await expect(
  foo(params),
).resolves.not.toThrowError();

// My other expects...

edited Apr 26 '22 at 18:47

answered Apr 06 '22 at 14:12

Camilo

2 Answers2