Update test assertions to pass with new cursor bias

This is a behavior change, but I honestly think it's an improvement.

crates/assistant/src/assistant_panel.rs

@@ -1625,6 +1625,7 @@ impl Conversation {
                 slash_command_registry,
             };
             this.set_language(cx);
+            this.ensure_trailing_user_message(cx);
             this.reparse_edit_suggestions(cx);
             this.count_remaining_tokens(cx);
             this
@@ -1704,13 +1705,33 @@ impl Conversation {
         cx: &mut ModelContext<Self>,
     ) {
         if *event == language::Event::Edited {
-            self.count_remaining_tokens(cx);
+            self.ensure_trailing_user_message(cx);
             self.reparse_edit_suggestions(cx);
             self.reparse_slash_command_calls(cx);
+            self.count_remaining_tokens(cx);
             cx.emit(ConversationEvent::MessagesEdited);
         }
     }
 
+    /// If we find a valid trailing message that isn't a user message, then add one
+    fn ensure_trailing_user_message(&mut self, cx: &mut ModelContext<Self>) {
+        let mut trailing_id = None;
+        for MessageAnchor { id, start } in self.message_anchors.iter().rev() {
+            if start.is_valid(self.buffer.read(cx)) {
+                if self.messages_metadata[id].role == Role::User {
+                    return;
+                } else {
+                    trailing_id = Some(*id);
+                    break;
+                }
+            }
+        }
+
+        if let Some(id) = trailing_id {
+            self.insert_message_after(id, Role::User, MessageStatus::Done, cx);
+        }
+    }
+
     pub(crate) fn count_remaining_tokens(&mut self, cx: &mut ModelContext<Self>) {
         let request = self.to_completion_request(cx);
         self.pending_token_count = cx.spawn(|this, mut cx| {
@@ -2207,6 +2228,7 @@ impl Conversation {
         for id in ids {
             if let Some(metadata) = self.messages_metadata.get_mut(&id) {
                 metadata.role.cycle();
+                self.ensure_trailing_user_message(cx);
                 cx.emit(ConversationEvent::MessagesEdited);
                 cx.notify();
             }

crates/editor/src/editor_tests.rs

@@ -6958,7 +6958,7 @@ async fn test_advance_downward_on_toggle_comment(cx: &mut gpui::TestAppContext)
     cx.assert_editor_state(indoc!(
         "fn a() {
              // dog();
-             catˇ();
+             ˇcat();
         }"
     ));
 
@@ -6974,7 +6974,7 @@ async fn test_advance_downward_on_toggle_comment(cx: &mut gpui::TestAppContext)
     });
     cx.assert_editor_state(indoc!(
         "fn a() {
-             // «dog()ˇ»;
+             «// dog()ˇ»;
              cat();
         }"
     ));
@@ -6992,7 +6992,7 @@ async fn test_advance_downward_on_toggle_comment(cx: &mut gpui::TestAppContext)
     cx.assert_editor_state(indoc!(
         "fn a() {
              // dog();
-             catˇ(ˇ);
+             ˇcat(ˇ);
         }"
     ));
 
@@ -7008,7 +7008,7 @@ async fn test_advance_downward_on_toggle_comment(cx: &mut gpui::TestAppContext)
     });
     cx.assert_editor_state(indoc!(
         "fn a() {
-             // ˇdˇog«()ˇ»;
+             ˇ// dˇog«()ˇ»;
              cat();
         }"
     ));

crates/editor/src/selections_collection.rs

@@ -534,20 +534,14 @@ impl<'a> MutableSelectionsCollection<'a> {
             }
         }
 
-        self.collection.disjoint = Arc::from_iter(selections.into_iter().map(|selection| {
-            let end_bias = if selection.end > selection.start {
-                Bias::Left
-            } else {
-                Bias::Right
-            };
-            Selection {
+        self.collection.disjoint =
+            Arc::from_iter(selections.into_iter().map(|selection| Selection {
                 id: selection.id,
-                start: buffer.anchor_after(selection.start),
-                end: buffer.anchor_at(selection.end, end_bias),
+                start: buffer.anchor_before(selection.start),
+                end: buffer.anchor_before(selection.end),
                 reversed: selection.reversed,
                 goal: selection.goal,
-            }
-        }));
+            }));
 
         self.collection.pending = None;
         self.selections_changed = true;