test: cover CLI chat delta event (#1921) (thanks @rmorse)

src/gateway/server-chat.agent-events.test.ts

@@ -0,0 +1,43 @@
+import { describe, expect, it, vi } from "vitest";
+
+import { createAgentEventHandler, createChatRunState } from "./server-chat.js";
+
+describe("agent event handler", () => {
+  it("emits chat delta for assistant text-only events", () => {
+    const nowSpy = vi.spyOn(Date, "now").mockReturnValue(1_000);
+    const broadcast = vi.fn();
+    const nodeSendToSession = vi.fn();
+    const agentRunSeq = new Map<string, number>();
+    const chatRunState = createChatRunState();
+    chatRunState.registry.add("run-1", { sessionKey: "session-1", clientRunId: "client-1" });
+
+    const handler = createAgentEventHandler({
+      broadcast,
+      nodeSendToSession,
+      agentRunSeq,
+      chatRunState,
+      resolveSessionKeyForRun: () => undefined,
+      clearAgentRunContext: vi.fn(),
+    });
+
+    handler({
+      runId: "run-1",
+      seq: 1,
+      stream: "assistant",
+      ts: Date.now(),
+      data: { text: "Hello world" },
+    });
+
+    const chatCalls = broadcast.mock.calls.filter(([event]) => event === "chat");
+    expect(chatCalls).toHaveLength(1);
+    const payload = chatCalls[0]?.[1] as {
+      state?: string;
+      message?: { content?: Array<{ text?: string }> };
+    };
+    expect(payload.state).toBe("delta");
+    expect(payload.message?.content?.[0]?.text).toBe("Hello world");
+    const sessionChatCalls = nodeSendToSession.mock.calls.filter(([, event]) => event === "chat");
+    expect(sessionChatCalls).toHaveLength(1);
+    nowSpy.mockRestore();
+  });
+});