Chai expect .to.throw(Error) not working as expected

Question

My assertion is:

    it.only('should throw an error if the transcription cannot happen', () => {
        expect(TranscriptLib.myFunc({ data }, '1')).to.throw(Error)
    })

My function is:

myFunc: (data, id) => {

                throw new Error({
                    message: 'Transcription failed',
                    error: someError
                })

However, when I run my test, the log shows:

     Error: [object Object]

and the test fails. What am I doing wrong?

IIRC `expect().to.throw` expects a function, it doesn’t use function-rewriting magic to wrap an expression with a `try`. — Ry-, Sep 06 '19 at 22:27

score 1 · Accepted Answer · answered Sep 17 '19 at 18:36

Your question is a duplicate of Mocha / Chai expect.to.throw not catching thrown errors

The most straightforward way to fix your issue would be to make the call to your code from an arrow function:

it.only('should throw an error if the transcription cannot happen', () => {   
  expect(() => TranscriptLib.myFunc({ data }, '1')).to.throw(Error)
})

As the answers on the other question show you can also use .bind to create a new function, and so on and so forth.

Chai expect .to.throw(Error) not working as expected

1 Answers1