test: add tests for sendBinary WebSocketClient feature

- TypeScript: WebSocketClient.test.ts verifies sendBinary() delegates to
  NativeWebSocketClient.sendBinaryDataFor() with the correct url and data.
  Adds transformIgnorePatterns to jest config for validator ESM package.
- Kotlin: WebSocketClientModuleImplTest covers the invalid-URL error path
  (URISyntaxException → promise.reject). Happy-path binary send requires
  android.util.Base64 and a live WebSocket, which are only available in
  instrumented (on-device) tests.

Author: bgardner8008

android/src/test/java/com/mattermost/networkclient/WebSocketClientModuleImplTest.kt

@@ -0,0 +1,35 @@
+package com.mattermost.networkclient
+
+import com.facebook.react.bridge.Promise
+import com.facebook.react.bridge.ReactApplicationContext
+import org.junit.Before
+import org.junit.Test
+import org.mockito.ArgumentCaptor
+import org.mockito.Mockito.mock
+import org.mockito.Mockito.verify
+import java.net.URISyntaxException
+
+class WebSocketClientModuleImplTest {
+    private lateinit var impl: WebSocketClientModuleImpl
+    private lateinit var promise: Promise
+
+    @Before
+    fun setUp() {
+        val mockContext = mock(ReactApplicationContext::class.java)
+        impl = WebSocketClientModuleImpl(mockContext)
+        promise = mock(Promise::class.java)
+    }
+
+    // Happy-path binary sends require a live WebSocket connection and android.util.Base64,
+    // which are only available in instrumented (on-device) tests. The base64 encoding and
+    // binary frame delivery are covered end-to-end by the mattermost-mobile test suite.
+
+    @Test
+    fun `sendBinaryDataFor rejects promise for malformed URL`() {
+        impl.sendBinaryDataFor("not a valid uri", "dGVzdA==", promise)
+
+        val captor = ArgumentCaptor.forClass(Throwable::class.java)
+        verify(promise).reject(captor.capture())
+        assert(captor.value is URISyntaxException)
+    }
+}

package.json

@@ -94,6 +94,9 @@
     "modulePathIgnorePatterns": [
       "<rootDir>/example/node_modules",
       "<rootDir>/lib/"
+    ],
+    "transformIgnorePatterns": [
+      "node_modules/(?!(@react-native|react-native|validator)/)"
     ]
   },
   "commitlint": {

src/WebSocketClient/__tests__/WebSocketClient.test.ts

@@ -0,0 +1,69 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+import {getOrCreateWebSocketClient} from '../index';
+import NativeWebSocketClient from '../NativeWebSocketClient';
+
+const mockNativeClient = NativeWebSocketClient as jest.Mocked<typeof NativeWebSocketClient>;
+
+jest.mock('../NativeWebSocketClient', () => ({
+    __esModule: true,
+    default: {
+        addListener: jest.fn(),
+        removeListeners: jest.fn(),
+        ensureClientFor: jest.fn().mockResolvedValue(undefined),
+        connectFor: jest.fn().mockResolvedValue(undefined),
+        disconnectFor: jest.fn().mockResolvedValue(undefined),
+        sendDataFor: jest.fn().mockResolvedValue(undefined),
+        sendBinaryDataFor: jest.fn().mockResolvedValue(undefined),
+        invalidateClientFor: jest.fn().mockResolvedValue(undefined),
+    },
+    WebSocketReadyState: {CONNECTING: 0, OPEN: 1, CLOSING: 2, CLOSED: 3},
+    WebSocketEvents: {
+        OPEN_EVENT: 'WebSocketClient-Open',
+        CLOSE_EVENT: 'WebSocketClient-Close',
+        ERROR_EVENT: 'WebSocketClient-Error',
+        MESSAGE_EVENT: 'WebSocketClient-Message',
+        READY_STATE_EVENT: 'WebSocketClient-ReadyState',
+    },
+}));
+
+// Each test uses a unique URL to avoid the module-level CLIENTS singleton state.
+let urlCounter = 0;
+const nextUrl = () => `ws://mattermost.example.com/api/v4/websocket?t=${++urlCounter}`;
+
+describe('WebSocketClient', () => {
+    beforeEach(() => {
+        jest.clearAllMocks();
+    });
+
+    it('should call sendDataFor when send() is invoked', async () => {
+        const url = nextUrl();
+        const {client} = await getOrCreateWebSocketClient(url);
+
+        client.send('hello');
+
+        expect(mockNativeClient.sendDataFor).toHaveBeenCalledWith(url, 'hello');
+    });
+
+    it('should call sendBinaryDataFor when sendBinary() is invoked', async () => {
+        const url = nextUrl();
+        const {client} = await getOrCreateWebSocketClient(url);
+        const base64Data = 'SGVsbG8gV29ybGQ=';
+
+        client.sendBinary(base64Data);
+
+        expect(mockNativeClient.sendBinaryDataFor).toHaveBeenCalledWith(url, base64Data);
+    });
+
+    it('should pass the exact url and data to sendBinaryDataFor', async () => {
+        const url = nextUrl();
+        const {client} = await getOrCreateWebSocketClient(url);
+        const encoded = 'dGVzdA==';
+
+        client.sendBinary(encoded);
+
+        expect(mockNativeClient.sendBinaryDataFor).toHaveBeenCalledTimes(1);
+        expect(mockNativeClient.sendBinaryDataFor).toHaveBeenCalledWith(url, encoded);
+    });
+});