test(ws): add connection error test

test/modules/WebSocket/intercept/websocket.connection.error.test.ts

@@ -0,0 +1,50 @@
+// @vitest-environment node-with-websocket
+import { vi, it, expect, beforeAll, afterEach, afterAll } from 'vitest'
+import { WebSocketInterceptor } from '../../../../src/interceptors/WebSocket'
+
+const interceptor = new WebSocketInterceptor()
+
+beforeAll(() => {
+  interceptor.apply()
+})
+
+afterEach(() => {
+  interceptor.removeAllListeners()
+})
+
+afterAll(() => {
+  interceptor.dispose()
+})
+
+it('simulates connection error by throwing inside the "connection" listener', async () => {
+  interceptor.on('connection', () => {
+    throw new Error('Mocked connection error')
+  })
+
+  const socket = new WebSocket('wss://example.com')
+
+  const openListener = vi.fn()
+  const closeListener = vi.fn()
+  const errorListener = vi.fn()
+
+  socket.onopen = openListener
+  socket.onerror = errorListener
+  socket.onclose = closeListener
+
+  await vi.waitFor(() => {
+    expect(errorListener).toHaveBeenCalledOnce()
+  })
+
+  expect(openListener).not.toHaveBeenCalled()
+  expect(closeListener).toHaveBeenCalledOnce()
+  expect(closeListener).toHaveBeenCalledWith(
+    expect.objectContaining({
+      type: 'close',
+      // Mark the closure as a server error.
+      code: 1011,
+      // Must include the error as the closure reason.
+      reason: 'Mocked connection error',
+    })
+  )
+  expect(socket.readyState).toBe(WebSocket.CLOSED)
+})