diff --git a/pool.test.ts b/pool.test.ts
index 85659b1..09fd0d1 100644
--- a/pool.test.ts
+++ b/pool.test.ts
@@ -2,7 +2,10 @@ import { afterEach, beforeEach, expect, test } from 'bun:test'
 
 import { SimplePool } from './pool.ts'
 import { finalizeEvent, generateSecretKey, getPublicKey, type Event } from './pure.ts'
-import { MockRelay } from './test-helpers.ts'
+import { useWebSocketImplementation } from './relay.ts'
+import { MockRelay, MockWebSocketClient } from './test-helpers.ts'
+
+useWebSocketImplementation(MockWebSocketClient)
 
 let pool: SimplePool
 let mockRelays: MockRelay[]
diff --git a/relay.test.ts b/relay.test.ts
index 73b3ae3..fde6982 100644
--- a/relay.test.ts
+++ b/relay.test.ts
@@ -1,8 +1,10 @@
 import { expect, test } from 'bun:test'
 
 import { finalizeEvent, generateSecretKey, getPublicKey } from './pure.ts'
-import { Relay } from './relay.ts'
-import { MockRelay } from './test-helpers.ts'
+import { Relay, useWebSocketImplementation } from './relay.ts'
+import { MockRelay, MockWebSocketClient } from './test-helpers.ts'
+
+useWebSocketImplementation(MockWebSocketClient)
 
 test('connectivity', async () => {
   const mockRelay = new MockRelay()
diff --git a/test-helpers.ts b/test-helpers.ts
index 4ba1f7d..2f3bca4 100644
--- a/test-helpers.ts
+++ b/test-helpers.ts
@@ -1,8 +1,10 @@
-import { Server } from 'mock-socket'
+import { Server, WebSocket } from 'mock-socket'
 
 import { finalizeEvent, type Event, getPublicKey, generateSecretKey } from './pure.ts'
 import { matchFilters, type Filter } from './filter.ts'
 
+export const MockWebSocketClient = WebSocket
+
 export function buildEvent(params: Partial<Event>): Event {
   return {
     id: '',