public void Callback_Method()
        {
            Assert.Throws <ArgumentNullException>(() => new VkontakteAuthButtonWidget().Callback(null));
            Assert.Throws <ArgumentException>(() => new VkontakteAuthButtonWidget().Callback(string.Empty));

            var widget = new VkontakteAuthButtonWidget();

            Assert.Null(widget.Callback());
            Assert.True(ReferenceEquals(widget.Callback("callback"), widget));
            Assert.Equal("callback", widget.Callback());
        }
 public void Constructors()
 {
   var widget = new VkontakteAuthButtonWidget();
   Assert.Null(widget.Callback());
   Assert.Null(widget.ElementId());
   Assert.Equal(VkontakteAuthButtonType.Standard, widget.Type());
   Assert.Null(widget.Url());
   Assert.Null(widget.Width());
 }
        public void Constructors()
        {
            var widget = new VkontakteAuthButtonWidget();

            Assert.Null(widget.Callback());
            Assert.Null(widget.ElementId());
            Assert.Equal(VkontakteAuthButtonType.Standard, widget.Type());
            Assert.Null(widget.Url());
            Assert.Null(widget.Width());
        }
    public void Callback_Method()
    {
      Assert.Throws<ArgumentNullException>(() => new VkontakteAuthButtonWidget().Callback(null));
      Assert.Throws<ArgumentException>(() => new VkontakteAuthButtonWidget().Callback(string.Empty));

      var widget = new VkontakteAuthButtonWidget();
      Assert.Null(widget.Callback());
      Assert.True(ReferenceEquals(widget.Callback("callback"), widget));
      Assert.Equal("callback", widget.Callback());
    }