Rawr Playground

// Code

use iced::Center;
use iced::widget::{Column, button, column, text};

pub fn main() -> iced::Result {
    iced::run(Counter::update, Counter::view)
}

#[derive(Default)]
struct Counter {
    value: i64,
}

#[derive(Debug, Clone, Copy)]
enum Message {
    Increment,
    Decrement,
}

impl Counter {
    fn update(&mut self, message: Message) {
        match message {
            Message::Increment => {
                self.value += 1;
            }
            Message::Decrement => {
                self.value -= 1;
            }
        }
    }

fn view(&self) -> Column<'_, Message> {
        column![
            button("Increment").on_press(Message::Increment),
            text(self.value).size(50),
            button("Decrement").on_press(Message::Decrement)
        ]
        .padding(20)
        .align_x(Center)
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use iced_test::{Error, simulator};

#[test]
    fn it_counts() -> Result<(), Error> {
        let mut counter = Counter { value: 0 };
        let mut ui = simulator(counter.view());

let _ = ui.click("Increment")?;
        let _ = ui.click("Increment")?;
        let _ = ui.click("Decrement")?;

for message in ui.into_messages() {
            counter.update(message);
        }

assert_eq!(counter.value, 1);

let mut ui = simulator(counter.view());
        assert!(ui.find("1").is_ok(), "Counter should display 1!");

Ok(())
    }
}

Messages (sent before preview, separated by newline)

// Outputready

Run (Ctrl/Cmd + Enter) to see the first frame.