add right sidebar auto-open to dock panels

crates/layout/tests/dock.rs

@@ -3,8 +3,10 @@ use gpui::{
     MouseDownEvent, MouseMoveEvent, MouseUpEvent, ParentElement as _, Pixels, Render, Styled as _,
     TestAppContext, VisualTestContext, Window, div, point, px,
 };
-use gpui_native_layout::dock::{Dock, DockState, PanelDescriptor, SplitDirection};
+use gpui_native_layout::dock::{Dock, DockSidebar, DockState, PanelDescriptor, SplitDirection};
 use gpui_native_theme::Theme;
+use std::cell::Cell;
+use std::rc::Rc;
 
 struct Panel {
     tag: &'static str,
@@ -18,10 +20,28 @@ impl Render for Panel {
     }
 }
 
+/// The right sidebar view a panel declares.
+struct SidePanel {
+    tag: &'static str,
+}
+
+impl Render for SidePanel {
+    fn render(&mut self, _window: &mut Window, _cx: &mut Context<Self>) -> impl IntoElement {
+        div()
+            .size_full()
+            .debug_selector(move || format!("side-{}", self.tag))
+    }
+}
+
 fn descriptor(tag: &'static str) -> PanelDescriptor {
     PanelDescriptor::new(tag, tag, move |_, cx| cx.new(|_| Panel { tag }).into())
 }
 
+fn descriptor_with_right_sidebar(tag: &'static str) -> PanelDescriptor {
+    PanelDescriptor::new(tag, tag, move |_, cx| cx.new(|_| Panel { tag }).into())
+        .right_sidebar(move |_, cx| cx.new(|_| SidePanel { tag }).into())
+}
+
 struct Harness {
     dock: Entity<DockState>,
 }
@@ -420,3 +440,101 @@ fn close_others_keeps_one_and_close_pane_empties() {
     open(&mut visual, &dock, "inbox");
     assert!(bounds(&mut visual, "test-dock-pane-0-tabs-tab-inbox").is_some());
 }
+
+struct SidebarHarness {
+    dock: Entity<DockState>,
+}
+
+impl Render for SidebarHarness {
+    fn render(&mut self, _window: &mut Window, _cx: &mut Context<Self>) -> impl IntoElement {
+        div()
+            .size_full()
+            .flex()
+            .flex_row()
+            .child(
+                div()
+                    .flex_1()
+                    .child(Dock::new("test-dock", self.dock.clone())),
+            )
+            .child(
+                div()
+                    .w(px(160.))
+                    .child(DockSidebar::new("test-dock-sidebar", self.dock.clone())),
+            )
+    }
+}
+
+fn sidebar_window(
+    cx: &mut TestAppContext,
+) -> (Entity<DockState>, Rc<Cell<bool>>, VisualTestContext) {
+    cx.update(Theme::init);
+    let dock = cx.update(DockState::new);
+    let opened = Rc::new(Cell::new(false));
+    let opened_for_dock = opened.clone();
+    let dock_for_window = dock.clone();
+    let window = cx.add_window(move |_, _| SidebarHarness {
+        dock: dock_for_window,
+    });
+    dock.update(cx, |dock, _| {
+        dock.on_open_right_sidebar(move |cx| {
+            opened_for_dock.set(true);
+            let _ = cx;
+        });
+    });
+    let mut visual = VisualTestContext::from_window(window.into(), cx);
+    visual.update(|window, cx| window.draw(cx).clear(cx));
+    (dock, opened, visual)
+}
+
+#[test]
+fn activating_a_panel_with_a_right_view_opens_the_sidebar() {
+    let mut cx = TestAppContext::single();
+    let (dock, opened, mut visual) = sidebar_window(&mut cx);
+    cx.update(|cx| {
+        dock.update(cx, |dock, cx| {
+            dock.register_panel(descriptor_with_right_sidebar("overview"), cx);
+            dock.register_panel(descriptor("inbox"), cx);
+        });
+    });
+
+    open(&mut visual, &dock, "overview");
+    assert!(
+        opened.get(),
+        "activation must ask the app to open the sidebar"
+    );
+    assert!(
+        bounds(&mut visual, "side-overview").is_some(),
+        "the sidebar shows the panel's own view"
+    );
+
+    // A panel without a right view leaves the sidebar showing the last one.
+    open(&mut visual, &dock, "inbox");
+    assert!(opened.get());
+    assert!(bounds(&mut visual, "side-overview").is_some());
+}
+
+#[test]
+fn closing_the_displayed_tab_falls_back_to_another_right_view() {
+    let mut cx = TestAppContext::single();
+    let (dock, opened, mut visual) = sidebar_window(&mut cx);
+    cx.update(|cx| {
+        dock.update(cx, |dock, cx| {
+            dock.register_panel(descriptor_with_right_sidebar("overview"), cx);
+            dock.register_panel(descriptor_with_right_sidebar("explore"), cx);
+        });
+    });
+    open(&mut visual, &dock, "overview");
+    open(&mut visual, &dock, "explore");
+    assert!(bounds(&mut visual, "side-explore").is_some());
+
+    cx.update(|cx| {
+        dock.update(cx, |dock, cx| dock.close_panel("explore", cx));
+    });
+    redraw(&mut visual);
+
+    assert!(
+        bounds(&mut visual, "side-overview").is_some(),
+        "the sidebar falls back to a remaining panel's view"
+    );
+    let _ = opened;
+}