ReferenceError: printStackTrace is not defined at Object in AngularJS

I have factory to print uncaught exception to the server side.

app.factory(
        "stacktraceService",
        function() {
            // "printStackTrace" is a global object.
            return({
                print: printStackTrace
            });
        }
    );

But when I run my test. It make error for all unit-test with message:

ReferenceError: printStackTrace is not defined at Object

How can i fix it?