新增 TurnList 组件，优化消息渲染逻辑

src/components/chat/AgentWorkspace.test.tsx

@@ -0,0 +1,97 @@
+/* eslint-disable @next/next/no-img-element */
+import "@testing-library/jest-dom";
+import React from "react";
+import { render } from "@testing-library/react";
+
+import { AgentWorkspace } from "./AgentWorkspace";
+import type { Message } from "./GlobalChatbox.types";
+
+const renderCounts = new Map<string, number>();
+
+jest.mock("next/image", () => ({
+  __esModule: true,
+  default: (props: React.ImgHTMLAttributes<HTMLImageElement>) => <img {...props} alt={props.alt ?? ""} />,
+}));
+
+jest.mock("framer-motion", () => ({
+  AnimatePresence: ({ children }: { children: React.ReactNode }) => <>{children}</>,
+  motion: {
+    div: ({ children, ...props }: React.HTMLAttributes<HTMLDivElement>) => <div {...props}>{children}</div>,
+  },
+}));
+
+jest.mock("./GlobalChatbox.parts", () => ({
+  TypingIndicator: () => <div>typing</div>,
+}));
+
+jest.mock("./AgentTurn", () => ({
+  AgentTurn: ({ message }: { message: Message }) => {
+    renderCounts.set(message.id, (renderCounts.get(message.id) ?? 0) + 1);
+    return <div data-testid={`turn-${message.id}`}>{message.content}</div>;
+  },
+}));
+
+describe("AgentWorkspace", () => {
+  const defaultProps = {
+    branchGroups: [],
+    branchTransition: null,
+    bottomRef: { current: null },
+    speakingMessageId: null,
+    speechState: "idle" as const,
+    onSpeak: jest.fn(),
+    onPauseSpeech: jest.fn(),
+    onResumeSpeech: jest.fn(),
+    onStopSpeech: jest.fn(),
+    isTtsSupported: false,
+    onRegenerate: jest.fn(),
+    onEditResubmit: jest.fn(),
+    onCycleBranch: jest.fn(),
+  };
+
+  beforeEach(() => {
+    renderCounts.clear();
+  });
+
+  it("keeps stable history turns from re-rendering while the last assistant message streams", () => {
+    const userMessage: Message = {
+      id: "user-1",
+      role: "user",
+      content: "question",
+    };
+    const assistantHistoryMessage: Message = {
+      id: "assistant-1",
+      role: "assistant",
+      content: "stable answer",
+    };
+    const streamingMessage: Message = {
+      id: "assistant-2",
+      role: "assistant",
+      content: "partial",
+    };
+
+    const { rerender } = render(
+      <AgentWorkspace
+        {...defaultProps}
+        isStreaming
+        messages={[userMessage, assistantHistoryMessage, streamingMessage]}
+      />,
+    );
+
+    const updatedStreamingMessage: Message = {
+      ...streamingMessage,
+      content: "partial with more tokens",
+    };
+
+    rerender(
+      <AgentWorkspace
+        {...defaultProps}
+        isStreaming
+        messages={[userMessage, assistantHistoryMessage, updatedStreamingMessage]}
+      />,
+    );
+
+    expect(renderCounts.get("user-1")).toBe(1);
+    expect(renderCounts.get("assistant-1")).toBe(1);
+    expect(renderCounts.get("assistant-2")).toBe(2);
+  });
+});