story-kit: merge 68_story_frontend_pipeline_state_stale_after_server_restart

frontend/src/api/client.test.ts

@@ -1,5 +1,5 @@
 import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
-import { api, resolveWsHost } from "./client";
+import { api, ChatWebSocket, resolveWsHost } from "./client";
 
 const mockFetch = vi.fn();
 
@@ -154,3 +154,179 @@ describe("api client", () => {
 		});
 	});
 });
+
+// ── ChatWebSocket reconnect tests ───────────────────────────────────────────
+
+interface MockWsInstance {
+	onopen: (() => void) | null;
+	onclose: (() => void) | null;
+	onmessage: ((e: { data: string }) => void) | null;
+	onerror: (() => void) | null;
+	readyState: number;
+	send: () => void;
+	close: () => void;
+	simulateClose: () => void;
+	simulateMessage: (data: Record<string, unknown>) => void;
+}
+
+function makeMockWebSocket() {
+	const instances: MockWsInstance[] = [];
+
+	class MockWebSocket {
+		static readonly CONNECTING = 0;
+		static readonly OPEN = 1;
+		static readonly CLOSING = 2;
+		static readonly CLOSED = 3;
+
+		onopen: (() => void) | null = null;
+		onclose: (() => void) | null = null;
+		onmessage: ((e: { data: string }) => void) | null = null;
+		onerror: (() => void) | null = null;
+		readyState = 0;
+
+		constructor(_url: string) {
+			instances.push(this as unknown as MockWsInstance);
+		}
+
+		send() {}
+
+		close() {
+			this.readyState = 3;
+			this.onclose?.();
+		}
+
+		simulateClose() {
+			this.readyState = 3;
+			this.onclose?.();
+		}
+
+		simulateMessage(data: Record<string, unknown>) {
+			this.onmessage?.({ data: JSON.stringify(data) });
+		}
+	}
+
+	return { MockWebSocket, instances };
+}
+
+describe("ChatWebSocket", () => {
+	beforeEach(() => {
+		vi.useFakeTimers();
+		const { MockWebSocket } = makeMockWebSocket();
+		vi.stubGlobal("WebSocket", MockWebSocket);
+		// Reset shared static state between tests
+		(ChatWebSocket as unknown as { sharedSocket: null }).sharedSocket = null;
+		(ChatWebSocket as unknown as { refCount: number }).refCount = 0;
+	});
+
+	afterEach(() => {
+		vi.useRealTimers();
+		vi.restoreAllMocks();
+	});
+
+	it("schedules reconnect after socket closes unexpectedly", () => {
+		const { MockWebSocket, instances } = makeMockWebSocket();
+		vi.stubGlobal("WebSocket", MockWebSocket);
+
+		const ws = new ChatWebSocket();
+		ws.connect({});
+
+		expect(instances).toHaveLength(1);
+
+		instances[0].simulateClose();
+
+		// No new socket created yet
+		expect(instances).toHaveLength(1);
+
+		// Advance past the initial 1s reconnect delay
+		vi.advanceTimersByTime(1001);
+
+		// A new socket should now have been created
+		expect(instances).toHaveLength(2);
+	});
+
+	it("delivers pipeline_state after reconnect", () => {
+		const { MockWebSocket, instances } = makeMockWebSocket();
+		vi.stubGlobal("WebSocket", MockWebSocket);
+
+		const onPipelineState = vi.fn();
+		const ws = new ChatWebSocket();
+		ws.connect({ onPipelineState });
+
+		// Simulate server restart
+		instances[0].simulateClose();
+		vi.advanceTimersByTime(1001);
+
+		// Server pushes pipeline_state on fresh connection
+		const freshState = {
+			upcoming: [{ story_id: "1_story_test", name: "Test", error: null }],
+			current: [],
+			qa: [],
+			merge: [],
+		};
+		instances[1].simulateMessage({ type: "pipeline_state", ...freshState });
+
+		expect(onPipelineState).toHaveBeenCalledWith(freshState);
+	});
+
+	it("does not reconnect after explicit close()", () => {
+		const { MockWebSocket, instances } = makeMockWebSocket();
+		vi.stubGlobal("WebSocket", MockWebSocket);
+
+		const ws = new ChatWebSocket();
+		ws.connect({});
+
+		// Explicit close disables reconnect
+		ws.close();
+
+		// Advance through both the DEV close-defer (250ms) and reconnect window
+		vi.advanceTimersByTime(2000);
+
+		// No new socket should be created
+		expect(instances).toHaveLength(1);
+	});
+
+	it("uses exponential backoff on repeated failures", () => {
+		const { MockWebSocket, instances } = makeMockWebSocket();
+		vi.stubGlobal("WebSocket", MockWebSocket);
+
+		const ws = new ChatWebSocket();
+		ws.connect({});
+
+		// First close → reconnects after 1s
+		instances[0].simulateClose();
+		vi.advanceTimersByTime(1001);
+		expect(instances).toHaveLength(2);
+
+		// Second close → reconnects after 2s (doubled)
+		instances[1].simulateClose();
+		vi.advanceTimersByTime(1500);
+		// Not yet (delay is now 2s)
+		expect(instances).toHaveLength(2);
+		vi.advanceTimersByTime(600);
+		expect(instances).toHaveLength(3);
+	});
+
+	it("resets reconnect delay after successful open", () => {
+		const { MockWebSocket, instances } = makeMockWebSocket();
+		vi.stubGlobal("WebSocket", MockWebSocket);
+
+		const ws = new ChatWebSocket();
+		ws.connect({});
+
+		// Disconnect and reconnect twice to raise the delay
+		instances[0].simulateClose();
+		vi.advanceTimersByTime(1001);
+
+		instances[1].simulateClose();
+		vi.advanceTimersByTime(2001);
+
+		// Simulate a successful open on third socket — resets delay to 1s
+		instances[2].onopen?.();
+
+		// Close again — should use the reset 1s delay
+		instances[2].simulateClose();
+		vi.advanceTimersByTime(1001);
+
+		expect(instances).toHaveLength(4);
+	});
+});