Workaround minifier bug

The function getStringByteSize() refers to an undefined variable in the
minified output. This works around this problem.

See babel/minify#430

Add a verify test for WebSocket.send() to make sure the private
getStringByteSize() can be called without an error being thrown.

Change-Id: I5513e53cc262d13fdc7434601c9557d0814655fc

src/tabris/WebSocket.js

@@ -131,6 +131,10 @@ Object.defineProperties(WebSocket.prototype, CONSTANTS);
 
 function getStringByteSize(input) {
   let len = 0;
+  // TODO: workaround for https://github.com/babel/babili/issues/430
+  if (!input.length) {
+    return 0;
+  }
   for (let i = 0; i < input.length; i++) {
     let code = input.charCodeAt(i);
     if (code <= 0x7f) {

test/tabris/WebSocket.verify.js

@@ -0,0 +1,38 @@
+const tabris = require('../../build/tabris/');
+const chai = require('chai');
+const expect = chai.expect;
+const sinon = require('sinon');
+const sandbox = sinon.sandbox.create();
+const restore = sandbox.restore.bind(sandbox);
+const stub = sandbox.stub.bind(sandbox);
+const sinonChai = require('sinon-chai');
+
+chai.use(sinonChai);
+
+describe('WebSocket', function() {
+
+  let webSocket;
+  let client;
+
+  beforeEach(function() {
+    client = stub({
+      call: () => {},
+      create: () => {},
+      get: () => {},
+      listen: () => {}
+    });
+    tabris._init(client);
+    webSocket = new tabris.WebSocket('ws://url.com', 'chat-protocol');
+  });
+
+  afterEach(restore);
+
+  it('calls send with string data', function() {
+    tabris._notify(webSocket._proxy.cid, 'open', {});
+
+    webSocket.send('hello');
+
+    expect(client.call).to.have.been.calledWith(webSocket._proxy.cid, 'send', {data: 'hello'});
+  });
+
+});