How to write a test which expects an Error to be thrown in Jasmine?

Question

I'm trying to write a test for the Jasmine Test Framework which expects an error. At the moment I'm using a Jasmine Node.js integration from GitHub.

In my Node.js module I have the following code:

throw new Error("Parsing is not possible"); 

Now I try to write a test which expects this error:

describe('my suite...', function() {     [..]     it('should not parse foo', function() {     [..]         expect(parser.parse(raw)).toThrow(new Error("Parsing is not possible"));     }); }); 

I tried also Error() and some other variants and just can't figure out how to make it work.

Answer 1

Try using an anonymous function instead:

expect( function(){ parser.parse(raw); } ).toThrow(new Error("Parsing is not possible")); 

you should be passing a function into the expect(...) call. Your incorrect code:

// incorrect: expect(parser.parse(raw)).toThrow(new Error("Parsing is not possible")); 

is trying to actually call parser.parse(raw) in an attempt to pass the result into expect(...),