Introduce tester feature flag

devtools/src/tester/null.rs

@@ -0,0 +1,51 @@
+use crate::Program;
+use crate::core::window;
+use crate::core::{Element, Theme};
+use crate::runtime::Task;
+use crate::widget::horizontal_space;
+
+use std::marker::PhantomData;
+
+pub struct Tester<P: Program> {
+    _type: PhantomData<P::Message>,
+}
+
+#[derive(Debug, Clone)]
+pub enum Message {}
+
+#[allow(missing_debug_implementations)]
+pub struct Tick<P: Program> {
+    _type: PhantomData<P::Message>,
+}
+
+impl<P: Program> Tester<P> {
+    pub fn new() -> Self {
+        Self { _type: PhantomData }
+    }
+
+    pub fn is_busy(&self) -> bool {
+        false
+    }
+
+    pub fn update(&mut self, _program: &P, _message: Message) -> Task<Tick<P>> {
+        Task::none()
+    }
+
+    pub fn tick(&mut self, _program: &P, _tick: Tick<P>) -> Task<Tick<P>> {
+        Task::none()
+    }
+
+    pub fn view<'a, T: 'static>(
+        &'a self,
+        _program: &P,
+        _window: window::Id,
+        _current: impl FnOnce() -> Element<'a, T, Theme, P::Renderer>,
+        _emulate: impl Fn(Tick<P>) -> T + 'a,
+    ) -> Element<'a, T, Theme, P::Renderer> {
+        horizontal_space().into()
+    }
+
+    pub fn controls(&self) -> Element<'_, Message, Theme, P::Renderer> {
+        horizontal_space().into()
+    }
+}

devtools/src/tester/recorder.rs

@@ -0,0 +1,183 @@
+use crate::core::layout;
+use crate::core::mouse;
+use crate::core::renderer;
+use crate::core::widget;
+use crate::core::widget::tree;
+use crate::core::{
+    self, Clipboard, Element, Event, Layout, Length, Point, Rectangle, Shell,
+    Size, Widget,
+};
+
+pub fn recorder<'a, Message, Theme, Renderer>(
+    content: impl Into<Element<'a, Message, Theme, Renderer>>,
+) -> Recorder<'a, Message, Theme, Renderer> {
+    Recorder::new(content)
+}
+
+#[allow(missing_debug_implementations)]
+pub struct Recorder<'a, Message, Theme, Renderer> {
+    content: Element<'a, Message, Theme, Renderer>,
+    on_event: Option<Box<dyn Fn(Event) -> Message + 'a>>,
+}
+
+impl<'a, Message, Theme, Renderer> Recorder<'a, Message, Theme, Renderer> {
+    pub fn new(
+        content: impl Into<Element<'a, Message, Theme, Renderer>>,
+    ) -> Self {
+        Self {
+            content: content.into(),
+            on_event: None,
+        }
+    }
+
+    pub fn on_event(
+        mut self,
+        on_event: impl Fn(Event) -> Message + 'a,
+    ) -> Self {
+        self.on_event = Some(Box::new(on_event));
+        self
+    }
+}
+
+impl<Message, Theme, Renderer> Widget<Message, Theme, Renderer>
+    for Recorder<'_, Message, Theme, Renderer>
+where
+    Renderer: core::Renderer,
+{
+    fn update(
+        &mut self,
+        state: &mut widget::Tree,
+        event: &Event,
+        layout: Layout<'_>,
+        cursor: mouse::Cursor,
+        renderer: &Renderer,
+        clipboard: &mut dyn Clipboard,
+        shell: &mut Shell<'_, Message>,
+        viewport: &Rectangle,
+    ) {
+        if shell.is_event_captured() {
+            return;
+        }
+
+        self.content.as_widget_mut().update(
+            state, event, layout, cursor, renderer, clipboard, shell, viewport,
+        );
+
+        if let Some(on_event) = &self.on_event {
+            match event {
+                Event::Mouse(event) => {
+                    if !cursor.is_over(layout.bounds()) {
+                        return;
+                    }
+
+                    match event {
+                        mouse::Event::ButtonPressed(_)
+                        | mouse::Event::ButtonReleased(_)
+                        | mouse::Event::WheelScrolled { .. } => {
+                            shell.publish(on_event(Event::Mouse(*event)));
+                        }
+                        mouse::Event::CursorMoved { position } => {
+                            shell.publish(on_event(Event::Mouse(
+                                mouse::Event::CursorMoved {
+                                    position: *position
+                                        - (layout.bounds().position()
+                                            - Point::ORIGIN),
+                                },
+                            )));
+                        }
+                        _ => {}
+                    }
+                }
+                Event::Keyboard(event) => {
+                    shell.publish(on_event(Event::Keyboard(event.clone())));
+                }
+                _ => {}
+            }
+        }
+    }
+
+    fn tag(&self) -> tree::Tag {
+        self.content.as_widget().tag()
+    }
+
+    fn state(&self) -> tree::State {
+        self.content.as_widget().state()
+    }
+
+    fn children(&self) -> Vec<widget::Tree> {
+        self.content.as_widget().children()
+    }
+
+    fn diff(&self, tree: &mut tree::Tree) {
+        self.content.as_widget().diff(tree);
+    }
+
+    fn size(&self) -> Size<Length> {
+        self.content.as_widget().size()
+    }
+
+    fn size_hint(&self) -> Size<Length> {
+        self.content.as_widget().size_hint()
+    }
+
+    fn layout(
+        &self,
+        tree: &mut widget::Tree,
+        renderer: &Renderer,
+        limits: &layout::Limits,
+    ) -> layout::Node {
+        self.content.as_widget().layout(tree, renderer, limits)
+    }
+
+    fn draw(
+        &self,
+        tree: &widget::Tree,
+        renderer: &mut Renderer,
+        theme: &Theme,
+        style: &renderer::Style,
+        layout: Layout<'_>,
+        cursor: mouse::Cursor,
+        viewport: &Rectangle,
+    ) {
+        self.content
+            .as_widget()
+            .draw(tree, renderer, theme, style, layout, cursor, viewport);
+    }
+
+    fn mouse_interaction(
+        &self,
+        state: &widget::Tree,
+        layout: Layout<'_>,
+        cursor: mouse::Cursor,
+        viewport: &Rectangle,
+        renderer: &Renderer,
+    ) -> mouse::Interaction {
+        self.content
+            .as_widget()
+            .mouse_interaction(state, layout, cursor, viewport, renderer)
+    }
+
+    fn operate(
+        &self,
+        state: &mut widget::Tree,
+        layout: Layout<'_>,
+        renderer: &Renderer,
+        operation: &mut dyn widget::Operation,
+    ) {
+        self.content
+            .as_widget()
+            .operate(state, layout, renderer, operation);
+    }
+}
+
+impl<'a, Message, Theme, Renderer> From<Recorder<'a, Message, Theme, Renderer>>
+    for Element<'a, Message, Theme, Renderer>
+where
+    Message: 'a,
+    Theme: 'a,
+    Renderer: core::Renderer + 'a,
+{
+    fn from(recorder: Recorder<'a, Message, Theme, Renderer>) -> Self {
+        Element::new(recorder)
+    }
+}