Faking out the Stripe CheckoutJS for Functional Tests. A simple drop-in replacement for https://checkout.stripe.com/checkout.js for your functional test environment.

stripe-checkout.js

var handler,
    StripeHandler = new Klass({
        initialize: function(token) {
            this._callback = token;
        },
        open: function(attrs) {
            var _self = this,
                button = $('<button id="dummy-stripe">').html(attrs.description),
                overlay = $('<div>', {id: 'dummy-stripe-overlay', style: "position: absolute; width: 20%; height: 40%; background-color: #fff; top: 30%; left: 40%; border: 4px solid #000; display: block; margin: auto auto;"}).html(button);
            $('body').append(overlay);
            $('#dummy-stripe').click(function(e) {
                e.preventDefault();
                $('#dummy-stripe-overlay').remove();
                _self._callback(undefined, undefined);
            });
        }
    }),
    StripeCheckout = new Klass({}).statics({
        configure: function(attrs) {
            return new StripeHandler(attrs.token);
        }
    });