我的测试堆栈由最新版本的 Selenium Server（2.33.0，又名 selenium-server-standalone-2.33.0.jar）、Mocha、Node.js 和 PhantomJS 组成。
我的问题与以下代码有关：
var webdriver = require('../../../lib/selenium/node_modules/selenium-webdriver/'),
driver = new webdriver.Builder().
withCapabilities({'browserName': 'phantomjs'}).
build();
driver.manage().timeouts().implicitlyWait(15000);
describe('Wordpress', function() {
it('should be able to log in', function(done) {
driver.get('http://#### REDACTED ####/wp-login.php');
driver.findElement(webdriver.By.css('#user_login')).sendKeys('#### REDACTED ####');
driver.findElement(webdriver.By.css('#user_pass')).sendKeys('#### REDACTED ####');
driver.findElement(webdriver.By.css('#wp-submit')).click();
// #wpwrap is an element on the Wordpress dashboard that is displayed once
// the user is logged in. By testing for its presence, we can determine
// if the login attempt succeeded.
driver.findElement(webdriver.By.css('#wpwrap')).then(function(v) {
done();
});
});
});
在我的本地系统 OS X 上，测试始终运行良好。但是，一旦将测试上传到我们的 CentOS 服务器（我们希望在其中进行持续集成测试），测试的行为就会非常奇怪。
Selenium Server 启动后，测试成功运行一次。从那时起，测试只成功了十次左右。重新启动 Selenium Server 保证测试将成功运行。事实上，如果每次运行测试都重新启动 Selenium Server，那么每次测试都会成功。
如何在不每次都重新启动 Selenium Server 的情况下使此测试成功？
非常感谢你的帮助！:)
更新：除了下面的错误日志之外，我偶尔还会收到以下错误：线程“Thread-21”中的异常 java.lang.OutOfMemoryError：无法创建新的本机线程
有关错误消息的详细信息如下：
成功的测试会从 Mocha 产生以下输出：
[s5rich@host ~]$ mocha test/selenium/acceptance/simple.js
Wordpress
✓ should be able to log in (2604ms)
1 passing (3 seconds)
成功的测试还会从 Selenium Server 产生以下输出：
23:21:50.517 INFO - Executing: [new session: {browserName=phantomjs}] at URL: /session)
23:21:50.527 INFO - Creating a new session for Capabilities [{browserName=phantomjs}]
23:21:50.547 INFO - executable: /usr/local/bin/phantomjs
23:21:50.547 INFO - port: 26515
23:21:50.547 INFO - arguments: [--webdriver=26515, --webdriver-logfile=/home/s5rich/phantomjsdriver.log]
23:21:50.547 INFO - environment: {}
PhantomJS is launching GhostDriver...
[INFO - 2013-07-24T05:21:50.923Z] GhostDriver - Main - running on port 26515
[INFO - 2013-07-24T05:21:51.435Z] Session [f235d040-f420-11e2-8d90-f50327bc3449] - CONSTRUCTOR - Desired Capabilities: {"browserName":"phantomjs"}
[INFO - 2013-07-24T05:21:51.435Z] Session [f235d040-f420-11e2-8d90-f50327bc3449] - CONSTRUCTOR - Negotiated Capabilities: {"browserName":"phantomjs","version":"1.9.1","driverName":"ghostdriver","driverVersion":"1.0.3","platform":"linux-unknown-32bit","javascriptEnabled":true,"takesScreenshot":true,"handlesAlerts":false,"databaseEnabled":false,"locationContextEnabled":false,"applicationCacheEnabled":false,"browserConnectionEnabled":false,"cssSelectorsEnabled":true,"webStorageEnabled":false,"rotatable":false,"acceptSslCerts":false,"nativeEvents":true,"proxy":{"proxyType":"direct"}}
[INFO - 2013-07-24T05:21:51.435Z] SessionManagerReqHand - _postNewSessionCommand - New Session Created: f235d040-f420-11e2-8d90-f50327bc3449
23:21:51.495 INFO - Done: /session
23:21:51.504 INFO - Executing: org.openqa.selenium.remote.server.handler.GetSessionCapabilities@46b78d at URL: /session/8750a6b4-ec7d-4313-a86d-04ac344b74f2)
23:21:51.505 INFO - Done: /session/8750a6b4-ec7d-4313-a86d-04ac344b74f2
23:21:51.520 INFO - Executing: [get: http://#### REDACTED ####/wp-login.php] at URL: /session/8750a6b4-ec7d-4313-a86d-04ac344b74f2/url)
23:21:51.821 INFO - Done: /session/8750a6b4-ec7d-4313-a86d-04ac344b74f2/url
23:21:51.827 INFO - Executing: [find element: By.selector: #user_login] at URL: /session/8750a6b4-ec7d-4313-a86d-04ac344b74f2/element)
23:21:51.874 INFO - Done: /session/8750a6b4-ec7d-4313-a86d-04ac344b74f2/element
23:21:51.883 INFO - Executing: [send keys: 0 org.openqa.selenium.support.events.EventFiringWebDriver$EventFiringWebElement@20788bf8, [#### REDACTED ####]] at URL: /session/8750a6b4-ec7d-4313-a86d-04ac344b74f2/element/0/value)
23:21:51.939 INFO - Done: /session/8750a6b4-ec7d-4313-a86d-04ac344b74f2/element/0/value
23:21:51.948 INFO - Executing: [find element: By.selector: #user_pass] at URL: /session/8750a6b4-ec7d-4313-a86d-04ac344b74f2/element)
23:21:51.965 INFO - Done: /session/8750a6b4-ec7d-4313-a86d-04ac344b74f2/element
23:21:52.001 INFO - Executing: [send keys: 1 org.openqa.selenium.support.events.EventFiringWebDriver$EventFiringWebElement@20788bf9, [#### REDACTED ####]] at URL: /session/8750a6b4-ec7d-4313-a86d-04ac344b74f2/element/1/value)
23:21:52.065 INFO - Done: /session/8750a6b4-ec7d-4313-a86d-04ac344b74f2/element/1/value
23:21:52.074 INFO - Executing: [find element: By.selector: #wp-submit] at URL: /session/8750a6b4-ec7d-4313-a86d-04ac344b74f2/element)
23:21:52.099 INFO - Done: /session/8750a6b4-ec7d-4313-a86d-04ac344b74f2/element
23:21:52.106 INFO - Executing: [click: 2 org.openqa.selenium.support.events.EventFiringWebDriver$EventFiringWebElement@20788bfa] at URL: /session/8750a6b4-ec7d-4313-a86d-04ac344b74f2/element/2/click)
23:21:52.842 INFO - Done: /session/8750a6b4-ec7d-4313-a86d-04ac344b74f2/element/2/click
23:21:52.850 INFO - Executing: [find element: By.selector: #wpwrap] at URL: /session/8750a6b4-ec7d-4313-a86d-04ac344b74f2/element)
23:21:52.871 INFO - Done: /session/8750a6b4-ec7d-4313-a86d-04ac344b74f2/element
失败的测试会从 Mocha 产生以下输出：
[s5rich@host ~]$ mocha test/selenium/acceptance/simple.js
Wordpress
1) should be able to log in
0 passing (2 seconds)
1 failing
1) Wordpress should be able to log in:
Uncaught UnknownError: Error Message => 'Unable to find element with css selector '#wpwrap''
caused by Request => {"headers":{"Accept":"application/json, image/png","Connection":"Keep-Alive","Content-Length":"42","Content-Type":"application/json; charset=utf-8","Host":"localhost:2897"},"httpVersion":"1.1","method":"POST","post":"{\"using\":\"css selector\",\"value\":\"#wpwrap\"}","url":"/element","urlParsed":{"anchor":"","query":"","file":"element","directory":"/","path":"/element","relative":"/element","port":"","host":"","password":"","user":"","userInfo":"","authority":"","protocol":"","source":"/element","queryKey":{},"chunks":["element"]},"urlOriginal":"/session/77a0a110-f421-11e2-a6fd-61cd002d7d02/element"}
Build info: version: '2.33.0', revision: '4e90c97', time: '2013-05-22 15:32:38'
System info: os.name: 'Linux', os.arch: 'i386', os.version: '2.6.32-042stab076.8', java.version: '1.7.0'
Driver info: driver.version: unknown
at new bot.Error (/home/s5rich/lib/selenium/node_modules_osx/selenium-webdriver/lib/atoms/error.js:108:18)
at Object.bot.response.checkResponse (/home/s5rich/lib/selenium/node_modules_osx/selenium-webdriver/lib/atoms/response.js:106:9)
at /home/s5rich/lib/selenium/node_modules_osx/selenium-webdriver/lib/webdriver/webdriver.js:262:20
at /home/s5rich/lib/selenium/node_modules_osx/selenium-webdriver/lib/goog/base.js:1112:15
at webdriver.promise.ControlFlow.runInNewFrame_ (/home/s5rich/lib/selenium/node_modules_osx/selenium-webdriver/lib/webdriver/promise.js:1431:20)
at notify (/home/s5rich/lib/selenium/node_modules_osx/selenium-webdriver/lib/webdriver/promise.js:315:12)
at notifyAll (/home/s5rich/lib/selenium/node_modules_osx/selenium-webdriver/lib/webdriver/promise.js:284:7)
at fulfill (/home/s5rich/lib/selenium/node_modules_osx/selenium-webdriver/lib/webdriver/promise.js:389:7)
at /home/s5rich/lib/selenium/node_modules_osx/selenium-webdriver/lib/webdriver/promise.js:1298:10
at /home/s5rich/lib/selenium/node_modules_osx/selenium-webdriver/lib/goog/base.js:1112:15
at webdriver.promise.ControlFlow.runInNewFrame_ (/home/s5rich/lib/selenium/node_modules_osx/selenium-webdriver/lib/webdriver/promise.js:1431:20)
at notify (/home/s5rich/lib/selenium/node_modules_osx/selenium-webdriver/lib/webdriver/promise.js:315:12)
at notifyAll (/home/s5rich/lib/selenium/node_modules_osx/selenium-webdriver/lib/webdriver/promise.js:284:7)
at fulfill (/home/s5rich/lib/selenium/node_modules_osx/selenium-webdriver/lib/webdriver/promise.js:389:7)
at /home/s5rich/lib/selenium/node_modules_osx/selenium-webdriver/lib/goog/base.js:1112:15
at webdriver.promise.ControlFlow.runInNewFrame_ (/home/s5rich/lib/selenium/node_modules_osx/selenium-webdriver/lib/webdriver/promise.js:1431:20)
at notify (/home/s5rich/lib/selenium/node_modules_osx/selenium-webdriver/lib/webdriver/promise.js:315:12)
at notifyAll (/home/s5rich/lib/selenium/node_modules_osx/selenium-webdriver/lib/webdriver/promise.js:284:7)
at fulfill (/home/s5rich/lib/selenium/node_modules_osx/selenium-webdriver/lib/webdriver/promise.js:389:7)
at /home/s5rich/lib/selenium/node_modules_osx/selenium-webdriver/lib/webdriver/promise.js:600:51
at /home/s5rich/lib/selenium/node_modules_osx/selenium-webdriver/lib/webdriver/http/http.js:96:5
at IncomingMessage.<anonymous> (/home/s5rich/lib/selenium/node_modules_osx/selenium-webdriver/http/index.js:113:7)
at IncomingMessage.EventEmitter.emit (events.js:117:20)
at _stream_readable.js:910:16
at process._tickCallback (node.js:415:13)
==== async task ====
WebDriver.findElement(By.cssSelector("#wpwrap"))
at webdriver.WebDriver.schedule (/home/s5rich/lib/selenium/node_modules_osx/selenium-webdriver/lib/webdriver/webdriver.js:246:15)
at webdriver.WebDriver.findElement (/home/s5rich/lib/selenium/node_modules_osx/selenium-webdriver/lib/webdriver/webdriver.js:685:17)
at Context.<anonymous> (/home/s5rich/test/selenium/acceptance/simple.js:12:10)
at Test.Runnable.run (/usr/local/lib/node_modules/mocha/lib/runnable.js:194:15)
at Runner.runTest (/usr/local/lib/node_modules/mocha/lib/runner.js:355:10)
at /usr/local/lib/node_modules/mocha/lib/runner.js:401:12
at next (/usr/local/lib/node_modules/mocha/lib/runner.js:281:14)
at /usr/local/lib/node_modules/mocha/lib/runner.js:290:7
at next (/usr/local/lib/node_modules/mocha/lib/runner.js:234:23)
at Object._onImmediate (/usr/local/lib/node_modules/mocha/lib/runner.js:258:5)
at processImmediate [as _immediateCallback] (timers.js:330:15)
失败的测试还会从 Selenium Server 产生以下输出：
23:25:34.742 INFO - Executing: [new session: {browserName=phantomjs}] at URL: /session)
23:25:34.743 INFO - Creating a new session for Capabilities [{browserName=phantomjs}]
23:25:34.744 INFO - executable: /usr/local/bin/phantomjs
23:25:34.744 INFO - port: 2897
23:25:34.744 INFO - arguments: [--webdriver=2897, --webdriver-logfile=/home/s5rich/phantomjsdriver.log]
23:25:34.744 INFO - environment: {}
PhantomJS is launching GhostDriver...
[INFO - 2013-07-24T05:25:34.879Z] GhostDriver - Main - running on port 2897
[INFO - 2013-07-24T05:25:35.270Z] Session [77a0a110-f421-11e2-a6fd-61cd002d7d02] - CONSTRUCTOR - Desired Capabilities: {"browserName":"phantomjs"}
[INFO - 2013-07-24T05:25:35.270Z] Session [77a0a110-f421-11e2-a6fd-61cd002d7d02] - CONSTRUCTOR - Negotiated Capabilities: {"browserName":"phantomjs","version":"1.9.1","driverName":"ghostdriver","driverVersion":"1.0.3","platform":"linux-unknown-32bit","javascriptEnabled":true,"takesScreenshot":true,"handlesAlerts":false,"databaseEnabled":false,"locationContextEnabled":false,"applicationCacheEnabled":false,"browserConnectionEnabled":false,"cssSelectorsEnabled":true,"webStorageEnabled":false,"rotatable":false,"acceptSslCerts":false,"nativeEvents":true,"proxy":{"proxyType":"direct"}}
[INFO - 2013-07-24T05:25:35.270Z] SessionManagerReqHand - _postNewSessionCommand - New Session Created: 77a0a110-f421-11e2-a6fd-61cd002d7d02
23:25:35.275 INFO - Done: /session
23:25:35.283 INFO - Executing: org.openqa.selenium.remote.server.handler.GetSessionCapabilities@13b4ce4 at URL: /session/b62d0c67-2000-439c-a0bd-f2c100350dee)
23:25:35.284 INFO - Done: /session/b62d0c67-2000-439c-a0bd-f2c100350dee
23:25:35.297 INFO - Executing: [get: http://#### REDACTED ####/wp-login.php] at URL: /session/b62d0c67-2000-439c-a0bd-f2c100350dee/url)
23:25:35.592 INFO - Done: /session/b62d0c67-2000-439c-a0bd-f2c100350dee/url
23:25:35.597 INFO - Executing: [find element: By.selector: #user_login] at URL: /session/b62d0c67-2000-439c-a0bd-f2c100350dee/element)
23:25:35.619 INFO - Done: /session/b62d0c67-2000-439c-a0bd-f2c100350dee/element
23:25:35.631 INFO - Executing: [send keys: 0 org.openqa.selenium.support.events.EventFiringWebDriver$EventFiringWebElement@240035bc, [#### REDACTED ####]] at URL: /session/b62d0c67-2000-439c-a0bd-f2c100350dee/element/0/value)
23:25:35.683 INFO - Done: /session/b62d0c67-2000-439c-a0bd-f2c100350dee/element/0/value
23:25:35.695 INFO - Executing: [find element: By.selector: #user_pass] at URL: /session/b62d0c67-2000-439c-a0bd-f2c100350dee/element)
23:25:35.712 INFO - Done: /session/b62d0c67-2000-439c-a0bd-f2c100350dee/element
23:25:35.723 INFO - Executing: [send keys: 1 org.openqa.selenium.support.events.EventFiringWebDriver$EventFiringWebElement@240035bd, [#### REDACTED ####]] at URL: /session/b62d0c67-2000-439c-a0bd-f2c100350dee/element/1/value)
23:25:35.783 INFO - Done: /session/b62d0c67-2000-439c-a0bd-f2c100350dee/element/1/value
23:25:35.800 INFO - Executing: [find element: By.selector: #wp-submit] at URL: /session/b62d0c67-2000-439c-a0bd-f2c100350dee/element)
23:25:35.822 INFO - Done: /session/b62d0c67-2000-439c-a0bd-f2c100350dee/element
23:25:35.832 INFO - Executing: [click: 2 org.openqa.selenium.support.events.EventFiringWebDriver$EventFiringWebElement@240035be] at URL: /session/b62d0c67-2000-439c-a0bd-f2c100350dee/element/2/click)
23:25:36.105 INFO - Done: /session/b62d0c67-2000-439c-a0bd-f2c100350dee/element/2/click
23:25:36.121 INFO - Executing: [find element: By.selector: #wpwrap] at URL: /session/b62d0c67-2000-439c-a0bd-f2c100350dee/element)
e = java.awt.HeadlessException:
No X11 DISPLAY variable was set, but this program performed an operation which requires it.
23:25:36.285 WARN - Exception thrown
org.openqa.selenium.NoSuchElementException: Error Message => 'Unable to find element with css selector '#wpwrap''
caused by Request => {"headers":{"Accept":"application/json, image/png","Connection":"Keep-Alive","Content-Length":"42","Content-Type":"application/json; charset=utf-8","Host":"localhost:2897"},"httpVersion":"1.1","method":"POST","post":"{\"using\":\"css selector\",\"value\":\"#wpwrap\"}","url":"/element","urlParsed":{"anchor":"","query":"","file":"element","directory":"/","path":"/element","relative":"/element","port":"","host":"","password":"","user":"","userInfo":"","authority":"","protocol":"","source":"/element","queryKey":{},"chunks":["element"]},"urlOriginal":"/session/77a0a110-f421-11e2-a6fd-61cd002d7d02/element"}
Command duration or timeout: 149 milliseconds
For documentation on this error, please visit: http://seleniumhq.org/exceptions/no_such_element.html
Build info: version: '2.33.0', revision: '4e90c97', time: '2013-05-22 15:32:38'
System info: os.name: 'Linux', os.arch: 'i386', os.version: '2.6.32-042stab076.8', java.version: '1.7.0'
Session ID: 77a0a110-f421-11e2-a6fd-61cd002d7d02
Driver info: org.openqa.selenium.phantomjs.PhantomJSDriver
Capabilities [{platform=LINUX, acceptSslCerts=false, javascriptEnabled=true, browserName=phantomjs, rotatable=false, driverVersion=1.0.3, locationContextEnabled=false, version=1.9.1, databaseEnabled=false, cssSelectorsEnabled=true, handlesAlerts=false, browserConnectionEnabled=false, proxy={proxyType=direct}, webStorageEnabled=false, nativeEvents=true, driverName=ghostdriver, applicationCacheEnabled=false, takesScreenshot=true}]
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at org.openqa.selenium.remote.ErrorHandler.createThrowable(ErrorHandler.java:191)
at org.openqa.selenium.remote.ErrorHandler.throwIfResponseFailed(ErrorHandler.java:145)
at org.openqa.selenium.remote.RemoteWebDriver.execute(RemoteWebDriver.java:554)
at org.openqa.selenium.remote.RemoteWebDriver.findElement(RemoteWebDriver.java:307)
at org.openqa.selenium.remote.RemoteWebDriver.findElementByCssSelector(RemoteWebDriver.java:396)
at org.openqa.selenium.By$ByCssSelector.findElement(By.java:407)
at org.openqa.selenium.remote.RemoteWebDriver.findElement(RemoteWebDriver.java:299)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.openqa.selenium.support.events.EventFiringWebDriver$2.invoke(EventFiringWebDriver.java:101)
at $Proxy1.findElement(Unknown Source)
at org.openqa.selenium.support.events.EventFiringWebDriver.findElement(EventFiringWebDriver.java:180)
at org.openqa.selenium.remote.server.handler.FindElement.call(FindElement.java:47)
at org.openqa.selenium.remote.server.handler.FindElement.call(FindElement.java:1)
at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at org.openqa.selenium.remote.server.DefaultSession$1.run(DefaultSession.java:169)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Caused by: org.openqa.selenium.remote.ScreenshotException: Screen shot has been taken
Build info: version: '2.33.0', revision: '4e90c97', time: '2013-05-22 15:32:38'
System info: os.name: 'Linux', os.arch: 'i386', os.version: '2.6.32-042stab076.8', java.version: '1.7.0'
Driver info: driver.version: EventFiringWebDriver
at org.openqa.selenium.remote.ErrorHandler.throwIfResponseFailed(ErrorHandler.java:125)
... 20 more
Caused by: org.openqa.selenium.remote.ErrorHandler$UnknownServerException: Error Message => 'Unable to find element with css selector '#wpwrap''
caused by Request => {"headers":{"Accept":"application/json, image/png","Connection":"Keep-Alive","Content-Length":"42","Content-Type":"application/json; charset=utf-8","Host":"localhost:2897"},"httpVersion":"1.1","method":"POST","post":"{\"using\":\"css selector\",\"value\":\"#wpwrap\"}","url":"/element","urlParsed":{"anchor":"","query":"","file":"element","directory":"/","path":"/element","relative":"/element","port":"","host":"","password":"","user":"","userInfo":"","authority":"","protocol":"","source":"/element","queryKey":{},"chunks":["element"]},"urlOriginal":"/session/77a0a110-f421-11e2-a6fd-61cd002d7d02/element"}
Build info: version: '2.33.0', revision: '4e90c97', time: '2013-05-22 15:32:38'
System info: os.name: 'Linux', os.arch: 'i386', os.version: '2.6.32-042stab076.8', java.version: '1.7.0'
Driver info: driver.version: unknown
23:25:36.293 WARN - Exception: Error Message => 'Unable to find element with css selector '#wpwrap''
caused by Request => {"headers":{"Accept":"application/json, image/png","Connection":"Keep-Alive","Content-Length":"42","Content-Type":"application/json; charset=utf-8","Host":"localhost:2897"},"httpVersion":"1.1","method":"POST","post":"{\"using\":\"css selector\",\"value\":\"#wpwrap\"}","url":"/element","urlParsed":{"anchor":"","query":"","file":"element","directory":"/","path":"/element","relative":"/element","port":"","host":"","password":"","user":"","userInfo":"","authority":"","protocol":"","source":"/element","queryKey":{},"chunks":["element"]},"urlOriginal":"/session/77a0a110-f421-11e2-a6fd-61cd002d7d02/element"}
Build info: version: '2.33.0', revision: '4e90c97', time: '2013-05-22 15:32:38'
System info: os.name: 'Linux', os.arch: 'i386', os.version: '2.6.32-042stab076.8', java.version: '1.7.0'
Driver info: driver.version: unknown