js: In remote.DriverService#start(), short-circuit polling the server status

if the child process dies.

Fixes #349

Author: jleyba

Diff for: javascript/node/selenium-webdriver/CHANGES.md

@@ -1,5 +1,8 @@
 ## v2.46.0-dev
 
+* FIXED: `remote.DriverService#start()` will now fail if the child process dies
+    while waiting for the server to start accepting requests. Previously, start
+    would continue to poll the server address until the timeout expired.
 * FIXED: 8564: `firefox.Driver#quit()` will wait for the Firefox process to
     terminate before deleting the temporary webdriver profile. This eliminates a
     race condition where Firefox would write profile data during shutdown,

Diff for: javascript/node/selenium-webdriver/remote/index.js

@@ -175,12 +175,14 @@ DriverService.prototype.start = function(opt_timeoutMs) {
 
       self.command_.fulfill(command);
 
-      command.result().then(function(result) {
-        self.address_.reject(result.code == null ?
+      var earlyTermination = command.result().then(function(result) {
+        var error = result.code == null ?
             Error('Server was killed with ' + result.signal) :
-            Error('Server exited with ' + result.code));
+            Error('Server terminated early with status ' + result.code);
+        self.address_.reject(error);
         self.address_ = null;
         self.command_ = null;
+        throw error;
       });
 
       var serverUrl = url.format({
@@ -191,9 +193,15 @@ DriverService.prototype.start = function(opt_timeoutMs) {
         pathname: self.path_
       });
 
-      return httpUtil.waitForServer(serverUrl, timeout).then(function() {
+      var ready = httpUtil.waitForServer(serverUrl, timeout).then(function() {
         return serverUrl;
       });
+
+      earlyTermination.thenCatch(function(e) {
+        ready.cancel(e.message);
+      });
+
+      return ready;
     });
   }));
 

Diff for: javascript/node/selenium-webdriver/test/remote_test.js

@@ -0,0 +1,49 @@
+// Copyright 2015 Software Freedom Conservancy
+// Copyright 2015 Selenium committers
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+//     You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+var assert = require('assert');
+
+var promise = require('../').promise;
+var remote = require('../remote');
+
+describe('DriverService', function() {
+
+  describe('start() fails if child-process dies', function() {
+    var service = new remote.DriverService(process.execPath, {
+      port: 1234,
+      args: ['-e', 'process.exit(1)']
+    })
+
+    after(function(done) {
+      service.kill().thenFinally(function() {
+        done();
+      });
+    });
+
+    it('', function(done) {
+      this.timeout(1000);
+      service.start(500).then(function() {
+        done(Error('expected to fail'));
+      }, function(e) {
+        try {
+          assert.equal('Server terminated early with status 1', e.message);
+          done();
+        } catch (e) {
+          done(e);
+        }
+      });
+    });
+  });
+});