Test always passing with Sinon and Chai

Question

I am using Mocha, Chai and Sinon to test some Node methods.

This test passes and when I change 'calledOnce' to 'calledTwice' it fails as expected.

 it('should call checkIfRoomExists once', function (done) {
            var check = sandbox.spy(RoomInfoModel, 'checkIfRoomExists');
            ViewBusiness.getViewToRender("thisisanoneknownroom", function (viewName) {
                expect(check.calledOnce).to.equal(true);
                done();
            })
        });

However when I try and follow tutorials the 'expect' is set up like this:

it('should call checkIfRoomExists once', function (done) {
        var check = sandbox.spy(RoomInfoModel, 'checkIfRoomExists');
        ViewBusiness.getViewToRender("thisisanoneknownroom", function (viewName) {
            expect(check).to.have.been.calledTwice;
            done();
        })
    });

Note that I am testing for 'calledTwice' in the second test. It still passes. If I change it to 'notCalled' it still passes. Basically it always passes.

What am I missing?

Answer 1

The only way I can reproduce the behavior you report is if I forget to call chai.use to add Sinon's assertions to it. For instance, this works as expected (the test fails):

const sinon = require("sinon");
const chai = require("chai");
const sinonChai = require("sinon-chai");
chai.use(sinonChai); // This is crucial to get Sinon's assertions.
const expect = chai.expect;

it("test", () => {
    const stub = sinon.stub();
    stub();
    expect(stub).to.have.been.calledTwice;
});

But if you take the same code and comment out chai.use(sinonChai) , then the test will pass!

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For fun, you can try expect(stub).to.have.been.platypus and that will pass too. Chai's expect interface tolerates nonsensical identifiers.