Preserve terminal feedback while coalescing repaints

internal/app/terminal_events_test.go

@@ -323,7 +323,7 @@ func TestProcessEventsTerminalRepaintsInDifferentRegionsBothSpeak(t *testing.T)
 	}
 }
 
-func TestProcessEventsDropsTrivialTerminalRepaintFragments(t *testing.T) {
+func TestProcessEventsPreservesShortTerminalRepaints(t *testing.T) {
 	speech := &fakeSpeechQueue{spoken: make(chan string, 4)}
 	adapter := &fakeAdapter{events: make(chan atspi.Event, 8)}
 	ctx, cancel := context.WithCancel(context.Background())
@@ -338,11 +338,16 @@ func TestProcessEventsDropsTrivialTerminalRepaintFragments(t *testing.T) {
 	terminal.TextCaretKnown = true
 	terminal.BrailleLineStart = 200
 	terminal.BrailleCaret = 205
-	repaintSequence(adapter, terminal, 100, "40")
-	select {
-	case text := <-speech.spoken:
-		t.Fatalf("trivial repaint fragment was presented as %q", text)
-	case <-time.After(2 * terminalRepaintDebounce):
+	for _, expected := range []string{"40", "OK", "猫"} {
+		repaintSequence(adapter, terminal, 100, expected)
+		select {
+		case text := <-speech.spoken:
+			if text != expected {
+				t.Fatalf("short repaint = %q, want %q", text, expected)
+			}
+		case <-time.After(3 * time.Second):
+			t.Fatalf("short repaint %q was lost", expected)
+		}
 	}
 	repaintSequence(adapter, terminal, 100, "Thinking (4s)")
 	select {
@@ -576,3 +581,106 @@ func TestProcessEventsPresentsTerminalFocusWithoutFollowingInsertion(t *testing.
 		t.Fatal("event loop did not stop")
 	}
 }
+
+// Run the real event handler synchronously so coalescing assertions do not
+// depend on a scheduler processing an entire burst before a timer fires.
+func terminalHandlerFixture(t *testing.T) (*accessibilityEventHandler, *[]string) {
+	t.Helper()
+	state := &eventLoopState{}
+	t.Cleanup(state.pending.clear)
+	spoken := []string{}
+	handler := &accessibilityEventHandler{
+		state: state, logger: slog.New(slog.DiscardHandler), adapter: &fakeAdapter{},
+		syncForeground: func() {}, webScripts: &webScriptController{},
+		speak: func(event atspi.Event, _ ...input.Intent) { spoken = append(spoken, event.Payload) },
+	}
+	handler.flushTerminalDeletion = func() {
+		event, _ := state.pending.terminalDeletion.take()
+		handler.speak(event)
+	}
+	return handler, &spoken
+}
+
+func TestTerminalRepaintsKeepTerminalIdentityAndFirstDeadline(t *testing.T) {
+	for _, differentTerminal := range []bool{false, true} {
+		t.Run(map[bool]string{false: "same terminal", true: "different bus"}[differentTerminal], func(t *testing.T) {
+			handler, spoken := terminalHandlerFixture(t)
+			terminal := atspi.Snapshot{BusName: ":1.10", Path: "/terminal", Role: "terminal"}
+			repaint := func(text string) {
+				deletion := atspi.NewEventWithPayload(atspi.TextDeletedEvent, terminal, "Old status")
+				insertion := atspi.NewEventWithPayload(atspi.TextInsertedEvent, terminal, text)
+				handler.handle(deletion)
+				handler.handle(insertion)
+			}
+			repaint("First status")
+			firstTimer := handler.state.pending.terminalRepaint.timer
+			if differentTerminal {
+				terminal.BusName = ":1.11"
+			}
+			repaint("Second status")
+			pending := &handler.state.pending.terminalRepaint
+			if differentTerminal {
+				if len(*spoken) != 1 || (*spoken)[0] != "First status" {
+					t.Fatalf("different terminal discarded earlier repaint: %v", *spoken)
+				}
+			} else if pending.timer != firstTimer {
+				t.Fatal("continuous repaint postponed the first deadline")
+			}
+			event, _ := pending.take()
+			if event.Payload != "Second status" {
+				t.Fatalf("latest repaint = %q", event.Payload)
+			}
+		})
+	}
+}
+
+func TestTerminalSeparateDeletionsPreserveEarlierFeedback(t *testing.T) {
+	handler, spoken := terminalHandlerFixture(t)
+	terminal := atspi.Snapshot{BusName: ":1.10", Path: "/terminal", Role: "terminal"}
+	first := atspi.NewEventWithPayload(atspi.TextDeletedEvent, terminal, "First deletion")
+	first.Detail1 = 100
+	second := atspi.NewEventWithPayload(atspi.TextDeletedEvent, terminal, "Second deletion")
+	second.Detail1 = 300
+	handler.handle(first)
+	handler.handle(second)
+	if len(*spoken) != 1 || (*spoken)[0] != first.Payload {
+		t.Fatalf("unrelated deletion discarded earlier feedback: %v", *spoken)
+	}
+	if handler.state.pending.terminalDeletion.event.Payload != second.Payload {
+		t.Fatal("later deletion was lost")
+	}
+}
+
+func TestTerminalHeldRepaintPreservesOrderAndRetiresOnFocusChange(t *testing.T) {
+	for _, next := range []string{"append", "deletion", "focus"} {
+		t.Run(next, func(t *testing.T) {
+			handler, spoken := terminalHandlerFixture(t)
+			terminal := atspi.Snapshot{BusName: ":1.10", Path: "/terminal", Role: "terminal"}
+			deletion := atspi.NewEventWithPayload(atspi.TextDeletedEvent, terminal, "Old status")
+			insertion := atspi.NewEventWithPayload(atspi.TextInsertedEvent, terminal, "Latest status")
+			handler.handle(deletion)
+			handler.handle(insertion)
+			event := atspi.NewEventWithPayload(atspi.TextInsertedEvent, terminal, "Appended output")
+			event.Detail1 = 300
+			switch next {
+			case "deletion":
+				event.Type, event.Payload = atspi.TextDeletedEvent, "Later deletion"
+			case "focus":
+				event = atspi.NewEvent(atspi.FocusEvent, atspi.Snapshot{BusName: ":1.10", Path: "/entry", Role: "text", Focused: true})
+			}
+			handler.handle(event)
+			if handler.state.pending.terminalRepaint.event.Type != "" {
+				t.Fatal("old repaint remains pending")
+			}
+			if next == "focus" {
+				for _, text := range *spoken {
+					if text == "Latest status" {
+						t.Fatal("old terminal spoke after focus moved to another control")
+					}
+				}
+			} else if len(*spoken) == 0 || (*spoken)[0] != "Latest status" {
+				t.Fatalf("later output overtook pending repaint: %v", *spoken)
+			}
+		})
+	}
+}