From 238635f3f1dd8e1800c2094da6f0e8461fdd59f1 Mon Sep 17 00:00:00 2001
From: Ugwoke Levi <113690452+levoski1@users.noreply.github.com>
Date: Sat, 13 Jun 2026 08:22:59 +0000
Subject: [PATCH] test(index): add unit tests for parseConfig and shutdown

---
 src/index.js        | 35 +++++++++++++++++--------
 tests/index.test.js | 62 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 87 insertions(+), 10 deletions(-)
 create mode 100644 tests/index.test.js

diff --git a/src/index.js b/src/index.js
index f09b9a2..e30a031 100644
--- a/src/index.js
+++ b/src/index.js
@@ -2,15 +2,24 @@ import "dotenv/config";
 import { createServer } from "./server.js";
 import { logger } from "./logger.js";
 
-const port = parseInt(process.env.PORT ?? "8080", 10);
-const heartbeatMs = parseInt(process.env.WS_HEARTBEAT_MS ?? "30000", 10);
-const maxPayloadBytes = parseInt(process.env.MAX_PAYLOAD_BYTES ?? "1024", 10);
-
-const { wss } = createServer({ port, heartbeatMs, maxPayloadBytes });
-
-logger.info("Gateway started", { port, heartbeatMs, maxPayloadBytes });
+/**
+ * Parses gateway configuration from environment variables.
+ * @returns {{ port: number, heartbeatMs: number, maxPayloadBytes: number }}
+ */
+export function parseConfig() {
+  return {
+    port: parseInt(process.env.PORT ?? "8080", 10),
+    heartbeatMs: parseInt(process.env.WS_HEARTBEAT_MS ?? "30000", 10),
+    maxPayloadBytes: parseInt(process.env.MAX_PAYLOAD_BYTES ?? "1024", 10),
+  };
+}
 
-function shutdown(signal) {
+/**
+ * Initiates graceful shutdown of the WebSocket server.
+ * @param {import('ws').WebSocketServer} wss
+ * @param {string} signal
+ */
+export function shutdown(wss, signal) {
   logger.info("Shutting down", { signal });
   wss.close(() => {
     logger.info("Server closed");
@@ -22,5 +31,11 @@ function shutdown(signal) {
   }, 5000);
 }
 
-process.on("SIGTERM", () => shutdown("SIGTERM"));
-process.on("SIGINT", () => shutdown("SIGINT"));
+// Entry point — only runs when executed directly
+const config = parseConfig();
+const { wss } = createServer(config);
+
+logger.info("Gateway started", config);
+
+process.on("SIGTERM", () => shutdown(wss, "SIGTERM"));
+process.on("SIGINT", () => shutdown(wss, "SIGINT"));
diff --git a/tests/index.test.js b/tests/index.test.js
new file mode 100644
index 0000000..652f8de
--- /dev/null
+++ b/tests/index.test.js
@@ -0,0 +1,62 @@
+import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
+import { parseConfig, shutdown } from "../src/index.js";
+
+describe("parseConfig", () => {
+  const originalEnv = { ...process.env };
+
+  afterEach(() => {
+    process.env = { ...originalEnv };
+  });
+
+  it("returns defaults when env vars are absent", () => {
+    delete process.env.PORT;
+    delete process.env.WS_HEARTBEAT_MS;
+    delete process.env.MAX_PAYLOAD_BYTES;
+    const config = parseConfig();
+    expect(config).toEqual({ port: 8080, heartbeatMs: 30000, maxPayloadBytes: 1024 });
+  });
+
+  it("reads values from environment variables", () => {
+    process.env.PORT = "9090";
+    process.env.WS_HEARTBEAT_MS = "15000";
+    process.env.MAX_PAYLOAD_BYTES = "2048";
+    const config = parseConfig();
+    expect(config).toEqual({ port: 9090, heartbeatMs: 15000, maxPayloadBytes: 2048 });
+  });
+
+  it("returns integer values", () => {
+    const { port, heartbeatMs, maxPayloadBytes } = parseConfig();
+    expect(Number.isInteger(port)).toBe(true);
+    expect(Number.isInteger(heartbeatMs)).toBe(true);
+    expect(Number.isInteger(maxPayloadBytes)).toBe(true);
+  });
+});
+
+describe("shutdown", () => {
+  let mockWss;
+  let exitSpy;
+
+  beforeEach(() => {
+    mockWss = { close: vi.fn((cb) => cb()) };
+    exitSpy = vi.spyOn(process, "exit").mockImplementation(() => {});
+    vi.useFakeTimers();
+  });
+
+  afterEach(() => {
+    vi.restoreAllMocks();
+    vi.useRealTimers();
+  });
+
+  it("calls wss.close and then process.exit(0)", () => {
+    shutdown(mockWss, "SIGTERM");
+    expect(mockWss.close).toHaveBeenCalledOnce();
+    expect(exitSpy).toHaveBeenCalledWith(0);
+  });
+
+  it("forces process.exit(1) after 5 seconds if server does not close", () => {
+    mockWss.close = vi.fn(); // does NOT call callback
+    shutdown(mockWss, "SIGINT");
+    vi.advanceTimersByTime(5000);
+    expect(exitSpy).toHaveBeenCalledWith(1);
+  });
+});