public void Width_Method()
        {
            Assert.Throws <ArgumentNullException>(() => IVkontakteAuthButtonWidgetExtensions.Width(null, 0));

            new VkontakteAuthButtonWidget().Do(widget =>
            {
                Assert.True(ReferenceEquals(widget.Width(1), widget));
                Assert.Equal("1", widget.Width());
            });
        }
        public void Dynamic_Method()
        {
            Assert.Throws <ArgumentNullException>(() => IVkontakteAuthButtonWidgetExtensions.Dynamic(null, "callback"));
            Assert.Throws <ArgumentNullException>(() => new VkontakteAuthButtonWidget().Dynamic(null));
            Assert.Throws <ArgumentException>(() => new VkontakteAuthButtonWidget().Dynamic(string.Empty));

            new VkontakteAuthButtonWidget().Do(widget =>
            {
                Assert.True(ReferenceEquals(widget.Dynamic("callback"), widget));
                Assert.Equal(VkontakteAuthButtonType.Dynamic, widget.Type());
                Assert.Equal("callback", widget.Callback());
            });
        }
        public void Standard_Method()
        {
            Assert.Throws <ArgumentNullException>(() => IVkontakteAuthButtonWidgetExtensions.Standard(null, "url"));
            Assert.Throws <ArgumentNullException>(() => new VkontakteAuthButtonWidget().Standard(null));
            Assert.Throws <ArgumentException>(() => new VkontakteAuthButtonWidget().Standard(string.Empty));

            new VkontakteAuthButtonWidget().Do(widget =>
            {
                Assert.True(ReferenceEquals(widget.Standard("url"), widget));
                Assert.Equal(VkontakteAuthButtonType.Standard, widget.Type());
                Assert.Equal("url", widget.Url());
            });
        }