Function gtk_test::find_child_by_name

pub fn find_child_by_name<C: IsA<Widget>, W: Clone + IsA<Object> + IsA<Widget>>(
    parent: &W, 
    name: &str
) -> Option<C>

Returns the child element which has the given name.

Example:

extern crate gtk;
#[macro_use]
extern crate gtk_test;

use gtk::{Button, ContainerExt, WidgetExt, Window, WindowType};

gtk::init().expect("GTK init failed");
let but = Button::new();
let w = Window::new(WindowType::Toplevel);

but.set_name("Button");
w.add(&but);

gtk_test::find_child_by_name::<Button, Window>(&w, "Button").expect("failed to find child");
// Or even better:
let but: Button = gtk_test::find_child_by_name(&w, "Button").expect("failed to find child");