How to test a prop update on React component

AirBnB’s Enzyme library provides an elegant solution to this question.

it provides a setProps method, that can be called on either a shallow or jsdom wrapper.

    it("Component should call componentWillReceiveProps on update", () => {
        const spy = sinon.spy(Component.prototype, "componentWillReceiveProps");
        const wrapper = shallow(<Component {...props} />);

        expect(spy.calledOnce).to.equal(false);
        wrapper.setProps({ prop: 2 });
        expect(spy.calledOnce).to.equal(true);
    });