Sinon: Test the order of function call and var change

Question

When we have

// arrange
var testVar = 0;
var testFunction = sandbox.stub();

// act
TestClass.TestMethod(); // it changes testVar and calls testFunction

Is there a way to test if testVar is changed before testFunction is called?

Edit: looks like there isn't. But! You can do something similar if the variable is an object property. Check my own answer below.

Answer 1

Ok, so looks like it can't really be done.

However, I did find a way to test with object properties. Example pseudo code:

before(function() {
    var functionCallOrder = [];

    document.body.classList.add = function() {
        functionCallOrder.push('added class');
    };

    Object.defineProperty(document.body, 'scrollTop', {
        set: function() {
            functionCallOrder.push('changed viewport location');
        }
    });

    it('should set a class before changing the viewport location'), function() {
            // act
            MyModule.methodThatDoesWhatTheDescriptionSays();

            // assert
            expect(functionCallOrder).to.deep.equal([
                'added class',
                'changed viewport location'
            ]);
    });
});