dart:io Improve raw_secure_server_socket_test to pin down problem.

tests/standalone/io/raw_secure_server_socket_test.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 //
 // VMOptions=
 // VMOptions=--short_socket_read
 // VMOptions=--short_socket_write
 // VMOptions=--short_socket_read --short_socket_write
 
 import "dart:async";
@@ skipping 153 matching lines @@
       int bytesWritten = 0;
       List<int> data = new List.fixedLength(messageSize);
 
       client.writeEventsEnabled = false;
       client.listen((event) {
         switch (event) {
           case RawSocketEvent.READ:
             Expect.isTrue(bytesWritten == 0);
             Expect.isTrue(client.available() > 0);
             var buffer = client.read();
-            data.setRange(bytesRead, buffer.length, buffer);
-            bytesRead += buffer.length;
+            if (buffer != null) {
+              data.setRange(bytesRead, buffer.length, buffer);
+              bytesRead += buffer.length;
+              for (var value in buffer) {
+                Expect.isTrue(value is int);
+                Expect.isTrue(value < 256 && value >= 0);
+              }
+            }
             if (bytesRead == data.length) {
               verifyTestData(data);
               client.writeEventsEnabled = true;
             }
             break;
           case RawSocketEvent.WRITE:
             Expect.isFalse(client.writeEventsEnabled);
+            Expect.equals(bytesRead, data.length);
+            for (int i = bytesWritten; i < data.length; ++i) {
+              Expect.isTrue(data[i] is int);
+              Expect.isTrue(data[i] < 256 && data[i] >= 0);
+            }
             bytesWritten += client.write(
                 data, bytesWritten, data.length - bytesWritten);
             if (bytesWritten < data.length) {
               client.writeEventsEnabled = true;
             }
             if (bytesWritten == data.length) {
               client.shutdown(SocketDirection.SEND);
             }
             break;
           case RawSocketEvent.READ_CLOSED:
             server.close();
             break;
           default: throw "Unexpected event $event";
         }
       });
     });
 
     RawSecureSocket.connect(HOST_NAME, server.port).then((socket) {
       int bytesRead = 0;
       int bytesWritten = 0;
       List<int> dataSent = createTestData();
       List<int> dataReceived = new List<int>.fixedLength(dataSent.length);
       socket.listen((event) {
         switch (event) {
           case RawSocketEvent.READ:
             Expect.isTrue(socket.available() > 0);
             var buffer = socket.read();
-            dataReceived.setRange(bytesRead, buffer.length, buffer);
-            bytesRead += buffer.length;
+            if (buffer != null) {
+              dataReceived.setRange(bytesRead, buffer.length, buffer);
+              bytesRead += buffer.length;
+            }
             break;
           case RawSocketEvent.WRITE:
             Expect.isTrue(bytesRead == 0);
             Expect.isFalse(socket.writeEventsEnabled);
             bytesWritten += socket.write(
                 dataSent, bytesWritten, dataSent.length - bytesWritten);
             if (bytesWritten < dataSent.length) {
               socket.writeEventsEnabled = true;
             }
             break;
@@ skipping 18 matching lines @@
   testArguments();
   testSimpleBind();
   testInvalidBind();
   testSimpleConnect(CERTIFICATE);
   testSimpleConnect("CN=localhost");
   testSimpleConnectFail("not_a_nickname");
   testSimpleConnectFail("CN=notARealDistinguishedName");
   testServerListenAfterConnect();
   testSimpleReadWrite();
 }