test: cover client reconnect failures

tests/transport-reconnect.test.ts

@@ -0,0 +1,163 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+
+type EventName = "open" | "close" | "error" | "message";
+type EventHandler = (...args: any[]) => void;
+
+const socketInstances: MockWebSocket[] = [];
+const pendingBehaviors: Array<"open" | "error"> = [];
+
+class MockWebSocket {
+  static readonly OPEN = 1;
+  static readonly CLOSED = 3;
+
+  readyState = 0;
+  sent: string[] = [];
+  private readonly handlers = new Map<EventName, EventHandler[]>();
+
+  constructor(public readonly url: string) {
+    socketInstances.push(this);
+    const behavior = pendingBehaviors.shift() ?? "open";
+
+    queueMicrotask(() => {
+      if (behavior === "open") {
+        this.readyState = MockWebSocket.OPEN;
+        this.emit("open");
+        return;
+      }
+
+      const error = new Error(`mock connect failure for ${url}`);
+      this.emit("error", error);
+      this.emit("close", 1006, Buffer.from("connect failed"));
+      this.readyState = MockWebSocket.CLOSED;
+    });
+  }
+
+  once(event: EventName, handler: EventHandler): this {
+    const onceHandler: EventHandler = (...args: any[]) => {
+      this.off(event, onceHandler);
+      handler(...args);
+    };
+    return this.on(event, onceHandler);
+  }
+
+  on(event: EventName, handler: EventHandler): this {
+    const existing = this.handlers.get(event) ?? [];
+    existing.push(handler);
+    this.handlers.set(event, existing);
+    return this;
+  }
+
+  off(event: EventName, handler: EventHandler): this {
+    const existing = this.handlers.get(event) ?? [];
+    this.handlers.set(
+      event,
+      existing.filter((candidate) => candidate !== handler)
+    );
+    return this;
+  }
+
+  send(message: string): void {
+    this.sent.push(message);
+  }
+
+  close(code = 1000, reason = ""):
+  void {
+    this.readyState = MockWebSocket.CLOSED;
+    this.emit("close", code, Buffer.from(reason));
+  }
+
+  emit(event: EventName, ...args: any[]): void {
+    for (const handler of [...(this.handlers.get(event) ?? [])]) {
+      handler(...args);
+    }
+  }
+}
+
+vi.mock("ws", () => ({
+  WebSocket: MockWebSocket
+}));
+
+describe("Yonexus.Client transport reconnect behavior", () => {
+  beforeEach(() => {
+    vi.useFakeTimers();
+    socketInstances.length = 0;
+    pendingBehaviors.length = 0;
+  });
+
+  afterEach(() => {
+    vi.useRealTimers();
+    vi.clearAllMocks();
+  });
+
+  it("CF-02: retries initial connect with exponential backoff when server is unreachable", async () => {
+    const { createClientTransport } = await import("../plugin/core/transport.js");
+    const onStateChange = vi.fn();
+    const onError = vi.fn();
+
+    pendingBehaviors.push("error", "error", "open");
+
+    const transport = createClientTransport({
+      config: {
+        mainHost: "ws://localhost:8787",
+        identifier: "client-a",
+        notifyBotToken: "stub-token",
+        adminUserId: "admin-user"
+      },
+      onMessage: vi.fn(),
+      onStateChange,
+      onError
+    });
+
+    await expect(transport.connect()).rejects.toThrow("mock connect failure");
+    expect(socketInstances).toHaveLength(1);
+    expect(transport.state).toBe("disconnected");
+
+    await vi.advanceTimersByTimeAsync(999);
+    expect(socketInstances).toHaveLength(1);
+
+    await vi.advanceTimersByTimeAsync(1);
+    expect(socketInstances).toHaveLength(2);
+
+    await vi.advanceTimersByTimeAsync(1_999);
+    expect(socketInstances).toHaveLength(2);
+
+    await vi.advanceTimersByTimeAsync(1);
+    expect(socketInstances).toHaveLength(3);
+    expect(transport.state).toBe("connected");
+    expect(onError.mock.calls.length).toBeGreaterThanOrEqual(2);
+    expect(onStateChange).toHaveBeenCalledWith("connecting");
+    expect(onStateChange).toHaveBeenCalledWith("connected");
+  });
+
+  it("CF-01: reconnects with backoff after network partition closes an established connection", async () => {
+    const { createClientTransport } = await import("../plugin/core/transport.js");
+
+    pendingBehaviors.push("open", "open");
+
+    const transport = createClientTransport({
+      config: {
+        mainHost: "ws://localhost:8787",
+        identifier: "client-a",
+        notifyBotToken: "stub-token",
+        adminUserId: "admin-user"
+      },
+      onMessage: vi.fn(),
+      onStateChange: vi.fn(),
+      onError: vi.fn()
+    });
+
+    await transport.connect();
+    expect(socketInstances).toHaveLength(1);
+    expect(transport.state).toBe("connected");
+
+    socketInstances[0].emit("close", 1006, Buffer.from("network partition"));
+    expect(transport.state).toBe("disconnected");
+
+    await vi.advanceTimersByTimeAsync(999);
+    expect(socketInstances).toHaveLength(1);
+
+    await vi.advanceTimersByTimeAsync(1);
+    expect(socketInstances).toHaveLength(2);
+    expect(transport.state).toBe("connected");
+  });
+});