Test a rejection with Chai as promised
Having version 5.1.0 of ChaiAsPromised, solution from Keithamus did not work for me - rejectedWith did not gave me the error object to assert, but "rejected" did:
return expect(foo())
.to.be.rejected
.and.be.an.instanceOf(Error)
.and.have.property('code', 'EFOO');
For asserting multiple properties
return expect(foo())
.to.be.rejected
.then(function(error) {
expect(error).to.have.property('name', 'my error message');
expect(error).to.have.property('code', 'EFOO');
});
If you're using Chai-As-Promised (as you say you are), then it allows for chaining off of rejectedWith
- and it sets the chain assertion object to be the error object - meaning anything after rejectedWith()
is now going to assert on the Error. This lets you do cool things like:
return expect(foo()).to.eventually
.be.rejectedWith("my error message")
.and.be.an.instanceOf(Error)
.and.have.property('code', 'EFOO');
Some of the chai methods also chain, so you can use that to make some quite deeply nested assertions about the error:
return expect(foo()).to.eventually
.be.rejectedWith("my error message")
.and.have.property('stack')
.that.includes('myfile.js:30')