Add an integration test for WebSocket

Summary:
**Motivation**

See if we can safely run a WebSocket test in Travis CI
Closes https://github.com/facebook/react-native/pull/11433

Differential Revision: D4342024

Pulled By: ericvicenti

fbshipit-source-id: 137fb0c39ed7ea3726e2778d5c0bdac4cef6ab89

IntegrationTests/WebSocketTest.js

@@ -0,0 +1,167 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ *
+ * @flow
+ */
+'use strict';
+
+var React = require('react');
+var ReactNative = require('react-native');
+var { View } = ReactNative;
+var { TestModule } = ReactNative.NativeModules;
+
+const DEFAULT_WS_URL = 'ws://localhost:5555/';
+
+const WS_EVENTS = [
+  'close',
+  'error',
+  'message',
+  'open',
+];
+const WS_STATES = [
+  /* 0 */ 'CONNECTING',
+  /* 1 */ 'OPEN',
+  /* 2 */ 'CLOSING',
+  /* 3 */ 'CLOSED',
+];
+
+type State = {
+  url: string;
+  fetchStatus: ?string;
+  socket: ?WebSocket;
+  socketState: ?number;
+  lastSocketEvent: ?string;
+  lastMessage: ?string | ?ArrayBuffer;
+  testMessage: string;
+  testExpectedResponse: string;
+};
+
+class WebSocketTest extends React.Component {
+  state: State = {
+    url: DEFAULT_WS_URL,
+    fetchStatus: null,
+    socket: null,
+    socketState: null,
+    lastSocketEvent: null,
+    lastMessage: null,
+    testMessage: 'testMessage',
+    testExpectedResponse: 'testMessage_response'
+  };
+
+  _waitFor = (condition: any, timeout: any, callback: any) => {
+    var remaining = timeout;
+    var t;
+    var timeoutFunction =  function() {
+      if (condition()) {
+        callback(true);
+        return;
+      }
+      remaining--;
+      if (remaining === 0) {
+        callback(false);
+      } else {
+        t = setTimeout(timeoutFunction,1000);
+      }
+    };
+    t = setTimeout(timeoutFunction,1000);
+  }
+
+  _connect = () => {
+    const socket = new WebSocket(this.state.url);
+    WS_EVENTS.forEach(ev => socket.addEventListener(ev, this._onSocketEvent));
+    this.setState({
+      socket,
+      socketState: socket.readyState,
+    });
+  };
+
+  _socketIsConnected = () => {
+    return this.state.socketState === 1; //'OPEN'
+  }
+
+  _socketIsDisconnected = () => {
+    return this.state.socketState === 3; //'CLOSED'
+  }
+
+  _disconnect = () => {
+    if (!this.state.socket) {
+      return;
+    }
+    this.state.socket.close();
+  };
+
+  _onSocketEvent = (event: any) => {
+    const state: any = {
+      socketState: event.target.readyState,
+      lastSocketEvent: event.type,
+    };
+    if (event.type === 'message') {
+      state.lastMessage = event.data;
+    }
+    this.setState(state);
+  };
+
+  _sendText = (text: string) => {
+    if (!this.state.socket) {
+      return;
+    }
+    this.state.socket.send(text);
+  };
+
+  _sendTestMessage = () => {
+    this._sendText(this.state.testMessage);
+  };
+
+  _receivedTestExpectedResponse = () => {
+    return (this.state.lastMessage === this.state.testExpectedResponse);
+  };
+
+  componentDidMount() {
+    this.testConnect();
+  }
+
+  testConnect = () => {
+    var component = this;
+    component._connect();
+    component._waitFor(component._socketIsConnected, 5, function(connectSucceeded) {
+      if (!connectSucceeded) {
+        TestModule.markTestPassed(false);
+        return;
+      }
+      component.testSendAndReceive();
+    });
+  }
+
+  testSendAndReceive = () => {
+    var component = this;
+    component._sendTestMessage();
+    component._waitFor(component._receivedTestExpectedResponse, 5, function(messageReceived) {
+      if (!messageReceived) {
+        TestModule.markTestPassed(false);
+        return;
+      }
+      component.testDisconnect();
+    });
+  }
+
+  testDisconnect = () => {
+    var component = this;
+    component._disconnect();
+    component._waitFor(component._socketIsDisconnected, 5, function(disconnectSucceeded) {
+      TestModule.markTestPassed(disconnectSucceeded);
+    });
+  }
+
+  render(): React.Element<any> {
+    return <View />;
+  }
+}
+
+WebSocketTest.displayName = 'WebSocketTest';
+
+module.exports = WebSocketTest;