My first attempt with unit testing

1

Can anyone help me find out why bar is still set to null?

describe("A spy", function () {

    var foo, bar = null;

    beforeEach(function () {
        foo = {
            setRandomNum: function (value) {
                bar = value
            }
        };

        spyOn(foo, 'setRandomNum');
    });

    it('should return a random number', function () {

        // Arrange
        var randomNum = Math.random();

        // Act
        foo.setRandomNum(randomNum);

        // Assert
        expect(foo.setRandomNum).toHaveBeenCalledWith(randomNum);
        expect(bar).toEqual(randomNum);

    });
});