T22: Collaboration

- presence: avatars ringed in each peer's color with where they are, press to
  follow; a breathing live dot; follow mode frames the view and stops on Escape
- remote cursors and selections painted over a field from its own layout
- comment threads with replies, reactions and resolve; a marker that opens a
  thread in a bubble; a sidebar of open and resolved threads
- annotations washed in their authors' colors, notes on hover
- suggestion mode: edits become suggestions word by word; track changes shows
  them struck and underlined, to accept or reject
- sharing: invite by email with checked chips, roles, the access list and who
  the link lets in, in one dialog
- primitives::hold_focus gives a mode its own focus, shared with ZenMode
- AvatarGroup's tuck and count shared; Avatar::ring_color; TagInput::check;
  TextInput::bounds_for_range; Popover::size
- icons: smile-plus, user-plus, message-square-diff
- gallery: the Collaboration page with scripted states

src/collab/tests.rs

@@ -0,0 +1,100 @@
+use gpui::{
+    AppContext as _, Context, Entity, Focusable, IntoElement, ParentElement, Render, Styled,
+    TestAppContext, VisualTestContext, Window, div,
+};
+
+use super::{FollowMode, Peer, Reply};
+use crate::{
+    forms,
+    forms::{Input, TextInput},
+    theme::Theme,
+};
+
+/// A field outside a followed view and one inside it, with what they asked: replies sent, follows stopped.
+struct Desk {
+    outside: Entity<TextInput>,
+    field: Entity<TextInput>,
+    following: bool,
+    sent: usize,
+    stopped: usize,
+}
+
+impl Render for Desk {
+    fn render(&mut self, _: &mut Window, cx: &mut Context<Self>) -> impl IntoElement {
+        let (send, stop) = (cx.entity(), cx.entity());
+        let peer = self.following.then(|| Peer::new("ada", "Ada", 0));
+        div().size_full().child(Input::new(&self.outside)).child(
+            FollowMode::new("follow", peer, move |_, cx| {
+                stop.update(cx, |desk, _| desk.stopped += 1)
+            })
+            .child(Reply::new("reply", &self.field, move |_, cx| {
+                send.update(cx, |desk, _| desk.sent += 1)
+            })),
+        )
+    }
+}
+
+fn open(following: bool, cx: &mut TestAppContext) -> (Entity<Desk>, &mut VisualTestContext) {
+    cx.update(|cx| {
+        Theme::init(cx);
+        forms::bind_keys(cx);
+    });
+    let (desk, cx) = cx.add_window_view(move |window, cx| Desk {
+        outside: cx.new(|cx| TextInput::new(window, cx)),
+        field: cx.new(|cx| TextInput::new(window, cx)),
+        following,
+        sent: 0,
+        stopped: 0,
+    });
+    cx.update(|window, cx| {
+        window.activate_window();
+        let field = desk.read(cx).field.clone();
+        window.focus(&field.focus_handle(cx));
+    });
+    cx.run_until_parked();
+    (desk, cx)
+}
+
+#[gpui::test]
+fn enter_sends_a_reply_only_with_words(cx: &mut TestAppContext) {
+    let (desk, cx) = open(false, cx);
+    cx.simulate_keystrokes("space enter");
+    assert_eq!(desk.read_with(cx, |desk, _| desk.sent), 0, "blank stays");
+    cx.simulate_input("agreed");
+    cx.simulate_keystrokes("enter");
+    assert_eq!(desk.read_with(cx, |desk, _| desk.sent), 1);
+}
+
+#[gpui::test]
+fn escape_stops_following_only_while_following(cx: &mut TestAppContext) {
+    let (desk, cx) = open(true, cx);
+    cx.simulate_keystrokes("escape");
+    assert_eq!(desk.read_with(cx, |desk, _| desk.stopped), 1);
+    desk.update(cx, |desk, cx| {
+        desk.following = false;
+        cx.notify();
+    });
+    cx.run_until_parked();
+    cx.simulate_keystrokes("escape");
+    assert_eq!(desk.read_with(cx, |desk, _| desk.stopped), 1);
+}
+
+#[gpui::test]
+fn following_begun_from_outside_still_stops_on_escape(cx: &mut TestAppContext) {
+    let (desk, cx) = open(false, cx);
+    cx.update(|window, cx| {
+        let outside = desk.read(cx).outside.focus_handle(cx);
+        window.focus(&outside);
+    });
+    desk.update(cx, |desk, cx| {
+        desk.following = true;
+        cx.notify();
+    });
+    cx.run_until_parked();
+    cx.update(|window, _| window.refresh());
+    cx.run_until_parked();
+    cx.simulate_keystrokes("escape");
+    assert_eq!(desk.read_with(cx, |desk, _| desk.stopped), 1);
+    let back = cx.update(|window, cx| desk.read(cx).outside.focus_handle(cx).is_focused(window));
+    assert!(back, "focus returns to where it was");
+}