How do I ensure that my log4j is being called once in my unit testing

Question

I am using sinon with nodejs .

How do I ensure that my log4j is being called once in my unit testing.

I am getting this error:

TypeError: Attempted to wrap undefined property info as function.

main.js:

let log = require('log4js').getLogger("main");

...
personDao.updatePerson(param,
                (updatePerson) => updatePersonCallBack(updatePersonResult));
...

let updatePersonCallBack= exports.updatePersonCallBack= (result) => {
    log.info("SUCCESS", result)
}

main.spec.js:

it('updatePersonCallBack', (done) => {

        let getInfoSpy = sinon.spy(log, "info");

        let updatePersonResult= 1;

        main.updatePersonCallBack(updatePersonResult);
        should.equal(getInfoSpy.callCount, 1);

        done();
    });

Answer 1

you need to import/require log in spec/test file as well so that spy will identify log and info as its method. As log is not declared in the spec/test file, it will throw undefined error.