test(copilot): exorcise carryover, no ghosts between turns

- Lock down no message carryover across client, event loop, and UI
- Verify EOS clears awaiting state and files are sent each turn

Signed-off-by: Jessie Frazelle <[email protected]>

Author: jessfraz

src/ml/copilot/run.rs

@@ -610,6 +610,55 @@ mod tests {
         }
     }
 
+    #[test]
+    fn client_message_content_does_not_carryover() {
+        let mut files = std::collections::HashMap::new();
+        files.insert("main.kcl".to_string(), b"cube(1)".to_vec());
+        let project_name = Some("proj".to_string());
+
+        let (m1, _) = build_user_message("first".into(), &files, &project_name);
+        let v1 = serde_json::to_value(&m1).unwrap();
+        assert_eq!(v1.get("content").unwrap().as_str().unwrap(), "first");
+
+        let (m2, _) = build_user_message("second".into(), &files, &project_name);
+        let v2 = serde_json::to_value(&m2).unwrap();
+        assert_eq!(v2.get("content").unwrap().as_str().unwrap(), "second");
+    }
+
+    #[test]
+    fn event_loop_two_submits_send_verbatim_and_files() {
+        let mut app = App::new();
+        let mut files = std::collections::HashMap::new();
+        files.insert("main.kcl".to_string(), b"cube(1)".to_vec());
+        let project_name = Some("proj".to_string());
+
+        // First submission
+        let s1 = app
+            .try_submit("hi im jess".into(), true)
+            .expect("first should send now");
+        let (m1, _len1) = build_user_message(s1, &files, &project_name);
+        let v1 = serde_json::to_value(&m1).unwrap();
+        assert_eq!(v1.get("content").unwrap().as_str().unwrap(), "hi im jess");
+        let files1 = v1.get("current_files").unwrap().as_object().unwrap();
+        assert!(files1.contains_key("main.kcl"));
+
+        // Simulate end-of-stream to clear awaiting state
+        assert!(app.on_end_of_stream(true).is_none());
+
+        // Second submission
+        let s2 = app
+            .try_submit("can you edit the kcl code to make the button blue".into(), true)
+            .expect("second should send now");
+        let (m2, _len2) = build_user_message(s2, &files, &project_name);
+        let v2 = serde_json::to_value(&m2).unwrap();
+        assert_eq!(
+            v2.get("content").unwrap().as_str().unwrap(),
+            "can you edit the kcl code to make the button blue"
+        );
+        let files2 = v2.get("current_files").unwrap().as_object().unwrap();
+        assert!(files2.contains_key("main.kcl"));
+    }
+
     #[test]
     fn tool_output_error_displays_error() {
         let mut app = App::new();

src/ml/copilot/state.rs

@@ -368,4 +368,26 @@ mod tests {
         let _ = app.handle_key_action(key(KeyCode::PageUp, KeyModifiers::NONE));
         assert!(app.msg_scroll <= 10);
     }
+
+    #[test]
+    fn lifecycle_two_submits_no_carryover() {
+        let mut app = App::new();
+        // Files not ready yet; first submit queues
+        assert!(app.try_submit("first".into(), false).is_none());
+        assert_eq!(app.queue.len(), 1);
+        // Scan done → send first
+        let s1 = app.on_scan_done();
+        assert_eq!(s1.as_deref(), Some("first"));
+        assert!(app.awaiting_response);
+
+        // EOS → allow next
+        let s_none = app.on_end_of_stream(true);
+        assert!(s_none.is_none());
+        assert!(!app.awaiting_response);
+
+        // Second submit should return exactly "second"
+        let s2 = app.try_submit("second".into(), true);
+        assert_eq!(s2.as_deref(), Some("second"));
+        assert!(app.queue.is_empty());
+    }
 }

src/ml/copilot/ui.rs

@@ -346,4 +346,56 @@ mod tests {
         }
         assert!(!row0b.contains("Proposed Changes"));
     }
+
+    #[test]
+    fn two_turns_no_prepend() {
+        let backend = TestBackend::new(60, 12);
+        let mut terminal = Terminal::new(backend).unwrap();
+        let mut app = App::new();
+        // Turn 1
+        app.events.push(ChatEvent::User("first".into()));
+        app.events
+            .push(ChatEvent::Server(kittycad::types::MlCopilotServerMessage::Delta {
+                delta: "Hello".into(),
+            }));
+        app.events
+            .push(ChatEvent::Server(kittycad::types::MlCopilotServerMessage::Delta {
+                delta: ", Jess".into(),
+            }));
+        app.events.push(ChatEvent::Server(
+            kittycad::types::MlCopilotServerMessage::EndOfStream { whole_response: None },
+        ));
+        // Turn 2
+        app.events.push(ChatEvent::User("second".into()));
+        app.events
+            .push(ChatEvent::Server(kittycad::types::MlCopilotServerMessage::Delta {
+                delta: "Hi again".into(),
+            }));
+        app.events.push(ChatEvent::Server(
+            kittycad::types::MlCopilotServerMessage::EndOfStream { whole_response: None },
+        ));
+
+        terminal.draw(|f| draw(f, &app)).unwrap();
+        let buf = terminal.backend().buffer();
+        let area = buf.area;
+        let mut content = String::new();
+        for y in 0..area.height {
+            for x in 0..area.width {
+                content.push(buf.get(x, y).symbol().chars().next().unwrap_or(' '));
+            }
+            content.push('\n');
+        }
+
+        // Ensure ordering and no prepend of first into second
+        let p1 = content.find("You> first").expect("missing first user line");
+        let p2 = content.find("You> second").expect("missing second user line");
+        assert!(p2 > p1);
+        assert!(
+            !content.contains("firstYou> second"),
+            "first message prepended to second user line"
+        );
+        // Assistant segments present separately
+        assert!(content.contains("ML-ephant> Hello, Jess"));
+        assert!(content.contains("ML-ephant> Hi again"));
+    }
 }