ChromeDriver 异常报告"target window already closed"无外设模式下

Question

我正在使用xUnit，SpecFlow，Selenium和无头Chrome来运行自动测试，但是每隔一段时间，我在localhost上运行时会遇到一系列崩溃，当尝试捕获最终浏览器窗口的屏幕截图时。

有两种方案，每种方案都在单独的功能文件中，这意味着它们并行运行。这似乎是第二个启动的场景总是失败。

以下是我创建浏览器实例的方式：

private static readonly string UserDataDir = new FileInfo(Assembly.GetExecutingAssembly().Location).DirectoryName;
var options = new ChromeOptions();
options.AddArguments("--disable-gpu");
options.AddArguments("--no-sandbox");
options.AddArgument("--ignore-certificate-errors");
options.AddArgument("--disable-web-security");
options.AddArgument("--allow-insecure-localhost");
options.AddArgument("--allow-running-insecure-content");
options.AddArgument("--acceptInsecureCerts=true");
options.AddArgument("--proxy-server='direct://'");
options.AddArgument("--proxy-bypass-list=*");
options.AddArgument("--disable-extensions");
options.AddArgument($@"--user-data-dir={UserDataDir}prof-{ProfileCounter++}");
options.AddArgument("--incognito");
options.AddArgument("--headless");
var svc = ChromeDriverService.CreateDefaultService();
svc.Port = Randomiser.Next(29700, 29900);
Context.Driver = new ChromeDriver(svc, options, TimeSpan.FromMinutes(2));
Context.Driver.Manage().Timeouts().ImplicitWait = TimeSpan.FromSeconds(ImplicitWaitSeconds);
Context.Driver.Manage().Timeouts().PageLoad = TimeSpan.FromSeconds(PageLoadSeconds);
Context.Driver.Manage().Timeouts().AsynchronousJavaScript = TimeSpan.FromSeconds(AsynchronousJavaScriptSeconds);

这是我关闭浏览器/驱动程序的方式：

[AfterScenario]
public void AfterScenario()
{
Context.Driver.Quit();
Context.Driver.Dispose();
Context.Driver = null;
}

这是发生异常的地方：

Context.Driver.GetScreenshot().SaveAsFile($@"{folder}{filename}.jpg", ScreenshotImageFormat.Jpeg);

下面是输出窗格中的完整异常：

------ Run test started ------
NUnit Adapter 3.10.0.21: Test execution started
Running all tests in C:gitTestingbinDebugTesting.dll
NUnit couldn't find any tests in C:gitTestingbinDebugTesting.dll
NUnit Adapter 3.10.0.21: Test execution complete
[xUnit.net 00:00:00.5180673]   Discovering: Testing
[xUnit.net 00:00:01.0205999]   Discovered:  Testing
[xUnit.net 00:00:01.0244487]   Starting:    Testing
[xUnit.net 00:00:14.7836328]     View the Daring Fireball talk show [FAIL]
[xUnit.net 00:00:14.7874843]       OpenQA.Selenium.NoSuchWindowException : no such window: target window already closed
from unknown error: web view not found
(Session info: headless chrome=65.0.3325.181)
(Driver info: chromedriver=2.38.551601 (edb21f07fc70e9027c746edd3201443e011a61ed),platform=Windows NT 6.1.7601 SP1 x86_64)
[xUnit.net 00:00:14.7898949]       Stack Trace:
[xUnit.net 00:00:14.7911454]            at OpenQA.Selenium.Remote.RemoteWebDriver.UnpackAndThrowOnError(Response errorResponse)
[xUnit.net 00:00:14.7916551]            at OpenQA.Selenium.Remote.RemoteWebDriver.Execute(String driverCommandToExecute, Dictionary`2 parameters)
[xUnit.net 00:00:14.7923841]            at OpenQA.Selenium.Remote.RemoteWebDriver.GetScreenshot()
[xUnit.net 00:00:14.7929467]         C:gitTestingStepDefinitionsCommonImplementationPageNavigationStepsImplementation.cs(90,0): at Testing.StepDefinitions.Common.Implementation.PageNavigationStepsImplementation.TakeScreenshot(String filename)
[xUnit.net 00:00:14.7933710]         C:gitTestingStepDefinitionsFeatureProperties.cs(122,0): at Testing.StepDefinitions.FeatureProperties.AfterScenario()
[xUnit.net 00:00:14.7939053]            at lambda_method(Closure , IContextManager )
[xUnit.net 00:00:14.7944826]            at TechTalk.SpecFlow.Bindings.BindingInvoker.InvokeBinding(IBinding binding, IContextManager contextManager, Object[] arguments, ITestTracer testTracer, TimeSpan& duration)
[xUnit.net 00:00:14.7949636]            at TechTalk.SpecFlow.Infrastructure.TestExecutionEngine.InvokeHook(IBindingInvoker invoker, IHookBinding hookBinding, HookType hookType)
[xUnit.net 00:00:14.7956197]            at TechTalk.SpecFlow.Infrastructure.TestExecutionEngine.FireEvents(HookType hookType)
[xUnit.net 00:00:14.7960898]            at TechTalk.SpecFlow.Infrastructure.TestExecutionEngine.FireScenarioEvents(HookType bindingEvent)
[xUnit.net 00:00:14.7966550]            at TechTalk.SpecFlow.Infrastructure.TestExecutionEngine.OnScenarioEnd()
[xUnit.net 00:00:14.7971662]            at TechTalk.SpecFlow.TestRunner.OnScenarioEnd()
[xUnit.net 00:00:14.7975471]            at SpecFlow.xUnitAdapter.SpecFlowPlugin.Runners.ScenarioTestCaseRunner.RunScenario(SpecFlowDocument gherkinDocument, Scenario scenario)
[xUnit.net 00:00:14.7979477]            at SpecFlow.xUnitAdapter.SpecFlowPlugin.Runners.ScenarioTestCaseRunner.<>c__DisplayClass9_0.<RunTestAsync>b__2()
[xUnit.net 00:00:14.7990766]       Output:
[xUnit.net 00:00:14.7995180]         Given I am on the https://daringfireball.net/ page
[xUnit.net 00:00:14.7998653]         -> done: PageNavigationSteps.IAmOnThePage("https://daringfir...") (11.5s)
[xUnit.net 00:00:14.8002840]         When I click element THE TALK SHOW found by text
[xUnit.net 00:00:14.8006231]         -> error: no such window: target window already closed
from unknown error: web view not found
(Session info: headless chrome=65.0.3325.181)
(Driver info: chromedriver=2.38.551601 (edb21f07fc70e9027c746edd3201443e011a61ed),platform=Windows NT 6.1.7601 SP1 x86_64)
[xUnit.net 00:00:14.8009870]         Then I arrive on the page titled Daring Fireball: The Talk Show
[xUnit.net 00:00:14.8013918]         -> skipped because of previous errors
[xUnit.net 00:00:18.8364913]   Finished:    Testing
========== Run test finished: 3 run (0:00:20.3) ==========

更新

步骤代码：

[When(@"I click element (.*)")]
public void IClickElement(string id)
{
try {
Context.Driver.FindElementsByPartialLinkText(id).FirstOrDefault();
} catch (Exception ex) {
var mssg = ex.Message; // debugger stops here (see exception below)
}
}

后场景代码：

[AfterScenario]
public void AfterScenario()
{
Context.Driver.Quit();
Context.Driver.Dispose();
Context.Driver = null;
Context.NgDriver = null;
}

虚假、不规则的错误消息：

no such window: target window already closed
from unknown error: web view not found
(Session info: headless chrome=65.0.3325.181)
(Driver info: chromedriver=2.38.551601 (edb21f07fc70e9027c746edd3201443e011a61ed),platform=Windows NT 6.1.7601 SP1 x86_64)

关联的堆栈跟踪：

at OpenQA.Selenium.Remote.RemoteWebDriver.UnpackAndThrowOnError(Response errorResponse)
at OpenQA.Selenium.Remote.RemoteWebDriver.Execute(String driverCommandToExecute, Dictionary`2 parameters)
at OpenQA.Selenium.Remote.RemoteWebDriver.FindElements(String mechanism, String value)
at OpenQA.Selenium.Remote.RemoteWebDriver.FindElementsByPartialLinkText(String partialLinkText)
at Testing.StepDefinitions.Common.Implementation.GenericNavigationStepsImplementations.FindElement(Matcher match, String id, String attributeValue) in C:gitTestingTestingStepDefinitionsCommonImplementationGenericNavigationStepsImplementations.cs:line 73

AfterScenario没有任何捕获，但随着屏幕截图尝试的删除，它不再抛出。在步骤定义的捕获中放置一个停止点表明浏览器已关闭。

更新 2

将铬更新为 66。异常消息：

no such window: target window already closed
from unknown error: web view not found
(Session info: headless chrome=66.0.3359.117)
(Driver info: chromedriver=2.38.551601 (edb21f07fc70e9027c746edd3201443e011a61ed),platform=Windows NT 6.1.7601 SP1 x86_64)

堆栈跟踪：

at OpenQA.Selenium.Remote.RemoteWebDriver.UnpackAndThrowOnError(Response errorResponse)
at OpenQA.Selenium.Remote.RemoteWebDriver.Execute(String driverCommandToExecute, Dictionary`2 parameters)
at OpenQA.Selenium.Remote.RemoteWebDriver.FindElements(String mechanism, String value)
at OpenQA.Selenium.Remote.RemoteWebDriver.FindElementsByPartialLinkText(String partialLinkText)
at Testing.StepDefinitions.Common.Implementation.GenericNavigationStepsImplementations.FindElement(Matcher match, String id, String attributeValue) in C:gitTestingTestingStepDefinitionsCommonImplementationGenericNavigationStepsImplementations.cs:line 73

相同的代码出现相同的错误。

Answer 1

正如所讨论的，这个问题可能是由于多种原因造成的

1. svc.Port = Randomiser.Next(29700, 29900);.您永远不应该自己分配端口，它也可能与其他一些程序端口冲突，甚至可以随机生成相同的端口号，这会导致问题

2. 您正在并行启动脚本。在极少数情况下，驱动程序启动时可能会出现争用条件，驱动程序可能无法启动。所以我会将工厂模式添加到我的驱动程序初始化代码中，如下所示

   public sealed class ChromeFactory 
   { 
   private static readonly object padlock = new object();
   ChromeFactory()
   {
   }
   public static WebDriver NewInstance
   {
   get
   {
   lock (padlock)
   {
   return new ChromeDriver();
   }
   }
   }
   }
   

并初始化驱动程序，如下所示

Context.Driver = ChromeFactory.NewInstance

3. 由于你有并行执行，我建议不要使用 #2 建议，而是设置一个浏览器限制计数的硒网格并使用它。这将使您的生活更加简单