Net::ReadTimeout: Net::ReadTimeout 和 Selenium::WebDriver::Error::UnknownError: 未知错误：Chrome 无法在 Rails 5.1.beta 系统测试上启动

热衷于将 Capybara 烘焙到新版 Rails (5.1) cfhttp://weblog.rubyonrails.org/2017/2/23/Rails-5-1-beta1/ http://weblog.rubyonrails.org/2017/2/23/Rails-5-1-beta1/

不过我遇到了问题。这是我的步骤。欢迎任何线索。

全新安装：

• Linux Ubuntu Desktop 16.10（Hyper-V 上的虚拟机），安装了 Chrome 并运行良好；
• 红宝石 2.4；
• Rails 5.1.beta。

1.- 创建一个简单的应用程序：

    ~$ ruby -v
    ruby 2.4.0p0 (2016-12-24 revision 57164) [x86_64-linux]
    ~$ rails -v
    Rails 5.1.0.beta1
    ~$ mkdir railsapps
    ~$ cd railsapps
    ~/railsapps$ rails new smoketestapp
    ~/railsapps$ cd smoketestapp
    ~/railsapps/smoketestapp$ rails generate scaffold post title:string body:text
    ~/railsapps/smoketestapp$ rails db:migrate

2.- 运行测试

    ~/railsapps/smoketestapp$ cat test/system/posts_test.rb
    require "application_system_test_case"

    class PostsTest < ApplicationSystemTestCase
      test "visiting the index" do
        visit posts_url

        assert_selector "h1", text: "Post"
      end
    end

     ~/railsapps/smoketestapp$ rake test TEST=test/system/posts_test.rb
    Run options: --seed 55778

    # Running:
    ...
    Error:
    PostsTest#test_visiting_the_index:
    Selenium::WebDriver::Error::WebDriverError: Unable to find chromedriver. Please download the server from http://chromedriver.storage.googleapis.com/index.html and place it somewhere on your PATH. More info at https://github.com/SeleniumHQ/selenium/wiki/ChromeDriver.
    ...
    1 runs, 0 assertions, 0 failures, 1 errors, 0 skips
     ~/railsapps/smoketestapp$

3.- 好的，让我们按照错误消息中的建议进行操作（安装chromedriver) :

     ~/railsapps/smoketestapp$ ls /usr/bin/google-chrome
    lrwxrwxrwx 1 root root 31 Mar 18 15:31 /usr/bin/google-chrome -> /etc/alternatives/google-chrome*
     ~/railsapps/smoketestapp$ echo $PATH 
    ...:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:...
     ~/railsapps/smoketestapp$ wget https://chromedriver.storage.googleapis.com/2.28/chromedriver_linux64.zip
     ~/railsapps/smoketestapp$ unzip chromedriver_linux64.zip
     ~/railsapps/smoketestapp$ sudo cp chromedriver /usr/local/bin
     ~/railsapps/smoketestapp$ ls /usr/local/bin
    total 7504
    drwxr-xr-x  2 root root    4096 Mar 19 19:05 ./
    drwxr-xr-x 10 root root    4096 Okt 12 22:42 ../
    -rwxr-xr-x  1 root root 7673176 Mar 19 19:05 chromedriver*
     ~/railsapps/smoketestapp$

4.- 好的。重试测试...

     ~/railsapps/smoketestapp$ rake test TEST=test/system/posts_test.rb
    Run options: --seed 51574

    # Running:
    ...
    Error:
    PostsTest#test_visiting_the_index:
    Net::ReadTimeout: Net::ReadTimeout test/system/posts _test.rb:5:in `block in '
    ...
    bin/rails test test/system/posts_test.rb:4
    ...
    1 runs, 0 assertions, 0 failures, 1 errors, 0 skips
     ~/railsapps/smoketestapp$

Not OK!

关于根本原因的线索'Net::ReadTimeout: Net::ReadTimeout'运行时给出错误信息rails -v在应用程序目录中，给出Selenium::WebDriver::Error::UnknownError: 未知错误：Chrome 无法启动:

    ~/railsapps/smoketestapp$ rails -v
    Run options: --seed 39896
    # Running:
    .......E
    Error:
    PostsTest#test_visiting_the_index:
    Selenium::WebDriver::Error::UnknownError: unknown error: Chrome failed to start: exited abnormally
      (Driver info: chromedriver=2.28.455506  (18f6627e265f442aeec9b6661a49fe819aeeea1f),platform=Linux 4.8.0-41-generic x86_64)
        test/system/posts_test.rb:5:in `block in <class:PostsTest>'
    Error:
    PostsTest#test_visiting_the_index:
    Net::ReadTimeout: Net::ReadTimeout

    bin/rails test test/system/posts_test.rb:4
    ...
    ~/railsapps/smoketestapp$

这是我直接从 Ruby 调用 Selenium WebDriver 时得到的结果：

    ~/railsapps/smoketestapp$ irb
    2.4.0 :001 > require "selenium-webdriver"
     => true
    2.4.0 :002 > driver = Selenium::WebDriver.for(:chrome)
    Net::ReadTimeout: Net::ReadTimeout
    from ~/.rvm/rubies/ruby-2.4.0/lib/ruby/2.4.0/net/protocol.rb:176:in `rbuf_fill'
    from ~/.rvm/rubies/ruby-2.4.0/lib/ruby/2.4.0/net/protocol.rb:154:in `readuntil'
    from ~/.rvm/rubies/ruby-2.4.0/lib/ruby/2.4.0/net/protocol.rb:164:in `readline'
    from ~/.rvm/rubies/ruby-2.4.0/lib/ruby/2.4.0/net/http/response.rb:40:in `read_status_line'
    from ~/.rvm/rubies/ruby-2.4.0/lib/ruby/2.4.0/net/http/response.rb:29:in `read_new'
    from ~/.rvm/rubies/ruby-2.4.0/lib/ruby/2.4.0/net/http.rb:1446:in `block in transport_request'
    from ~/.rvm/rubies/ruby-2.4.0/lib/ruby/2.4.0/net/http.rb:1443:in `catch'
    from ~/.rvm/rubies/ruby-2.4.0/lib/ruby/2.4.0/net/http.rb:1443:in `transport_request'
    from ~/.rvm/rubies/ruby-2.4.0/lib/ruby/2.4.0/net/http.rb:1416:in `request'
    from ~/.rvm/rubies/ruby-2.4.0/lib/ruby/2.4.0/net/http.rb:1409:in `block in request'
    from ~/.rvm/rubies/ruby-2.4.0/lib/ruby/2.4.0/net/http.rb:877:in `start'
    from ~/.rvm/rubies/ruby-2.4.0/lib/ruby/2.4.0/net/http.rb:1407:in `request'
    from ~/.rvm/gems/ruby-2.4.0/gems/selenium-webdriver-3.3.0/lib/selenium/webdriver/remote/http/default.rb:124:in `response_for'
    from ~/.rvm/gems/ruby-2.4.0/gems/selenium-webdriver-3.3.0/lib/selenium/webdriver/remote/http/default.rb:78:in `request'
    from ~/.rvm/gems/ruby-2.4.0/gems/selenium-webdriver-3.3.0/lib/selenium/webdriver/remote/http/common.rb:61:in `call'
    from ~/.rvm/gems/ruby-2.4.0/gems/selenium-webdriver-3.3.0/lib/selenium/webdriver/remote/bridge.rb:669:in `raw_execute'
    from ~/.rvm/gems/ruby-2.4.0/gems/selenium-webdriver-3.3.0/lib/selenium/webdriver/remote/bridge.rb:108:in `create_session'
    from ~/.rvm/gems/ruby-2.4.0/gems/selenium-webdriver-3.3.0/lib/selenium/webdriver/remote/bridge.rb:71:in `initialize'
    from ~/.rvm/gems/ruby-2.4.0/gems/selenium-webdriver-3.3.0/lib/selenium/webdriver/chrome/bridge.rb:52:in `initialize'
    from ~/.rvm/gems/ruby-2.4.0/gems/selenium-webdriver-3.3.0/lib/selenium/webdriver/common/driver.rb:61:in `new'
    from ~/.rvm/gems/ruby-2.4.0/gems/selenium-webdriver-3.3.0/lib/selenium/webdriver/common/driver.rb:61:in `for'
    from ~/.rvm/gems/ruby-2.4.0/gems/selenium-webdriver-3.3.0/lib/selenium/webdriver.rb:87:in `for'
    from (irb):2
    from ~/.rvm/rubies/ruby-2.4.0/bin/irb:11:in `<main>'
    2.4.0 :003 > exit
    ~/railsapps/smoketestapp$

任何帮助表示赞赏，谢谢

Varus

Update:

发现问题，查看 Selenium 驱动程序的日志文件。为此，我在 IRB 中输入以下内容：

    require "selenium-webdriver"
    Selenium::WebDriver::Chrome.driver_path="/usr/local/bin/chromedriver"
    Selenium::WebDriver.for :chrome, :service_log_path => "/tmp/cd.log"
    driver = Selenium::WebDriver.for(:chrome)

跟踪日志文件确定了这一点：chrome 无法启动：

    ~/railsapps/smoketestapp$ tail /tmp/cd.log
       ...
    [0.247][INFO]: Launching chrome: /opt/google/chrome/google-chrome --disable-background-networking --disable-client-side-phishing-detection --disable-component-update --disable-default-apps --disable-hang-monitor --disable-prompt-on-repost --disable-web-resources --enable-logging --full-memory-crash-report --ignore-certificate-errors --load-extension=/tmp/.org.chromium.Chromium.Pdre6o/internal --logging-level=1 --metrics-recording-only --no-first-run --password-store=basic --remote-debugging-port=12264 --safebrowsing-disable-auto-update --safebrowsing-disable-download-protection --use-mock-keychain --user-data-dir=/tmp/.org.chromium.Chromium.mHJaEd data:,
    [0.250][WARNING]: PAC support disabled because there is no system implementation
    [20.281][INFO]: RESPONSE InitSession unknown error: Chrome failed to start: exited abnormally
    ~/railsapps/smoketestapp$

最后我发现通过 PuTTY 远程调用 chrome 不起作用（这就是我一直在做的事情），尽管直接在虚拟机（在终端服务器中）上执行相同的操作是有效的.

在腻子上：

    ~$ google-chrome
    [3938:3938:0320/213941.129923:ERROR:browser_main_loop.cc(279)] Gtk: cannot open display:

然而，它直接在虚拟机上运行。

不幸的是，我的快乐是短暂的，因为我遇到了另一个错误，但那是另一个故事了：

            irb(main):001:0> require "selenium-webdriver"
    => true
    irb(main):002:0> Selenium::WebDriver::Chrome.driver_path="/usr/local/bin/chromedriver"
    => "/usr/local/bin/chromedriver"
    irb(main):003:0> driver = Selenium::WebDriver.for(:chrome)
    => #<Selenium::WebDriver::Driver:0x59d7c889a916c6b8 browser=:chrome>
    irb(main):004:0> driver.navigate.to("http://www.google.com")
    Selenium::WebDriver::Error::UnknownError: unknown error: Runtime.executionContextCreated has invalid 'context': {"auxData":{"frameId":"10797.1","isDefault":true},"id":1,"name":"","origin":"://"}
      (Session info: chrome=57.0.2987.110)
      (Driver info: chromedriver=2.4.226074,platform=Linux 4.8.0-41-generic x86_64)
            from ~/.rvm/rubies/ruby-2.4.0/lib/ruby/gems/2.4.0/gems/selenium-webdriver-3.3.0/lib/selenium/webdriver/remote/response.rb:69:in `assert_ok'
            from ~/.rvm/rubies/ruby-2.4.0/lib/ruby/gems/2.4.0/gems/selenium-webdriver-3.3.0/lib/selenium/webdriver/remote/response.rb:32:in `initialize'
            from ~/.rvm/rubies/ruby-2.4.0/lib/ruby/gems/2.4.0/gems/selenium-webdriver-3.3.0/lib/selenium/webdriver/remote/http/common.rb:83:in `new'
            from ~/.rvm/rubies/ruby-2.4.0/lib/ruby/gems/2.4.0/gems/selenium-webdriver-3.3.0/lib/selenium/webdriver/remote/http/common.rb:83:in `create_response'
            from ~/.rvm/rubies/ruby-2.4.0/lib/ruby/gems/2.4.0/gems/selenium-webdriver-3.3.0/lib/selenium/webdriver/remote/http/default.rb:107:in `request'
            from ~/.rvm/rubies/ruby-2.4.0/lib/ruby/gems/2.4.0/gems/selenium-webdriver-3.3.0/lib/selenium/webdriver/remote/http/common.rb:61:in `call'
            from ~/.rvm/rubies/ruby-2.4.0/lib/ruby/gems/2.4.0/gems/selenium-webdriver-3.3.0/lib/selenium/webdriver/remote/bridge.rb:669:in `raw_execute'
            from ~/.rvm/rubies/ruby-2.4.0/lib/ruby/gems/2.4.0/gems/selenium-webdriver-3.3.0/lib/selenium/webdriver/remote/bridge.rb:647:in `execute'
            from ~/.rvm/rubies/ruby-2.4.0/lib/ruby/gems/2.4.0/gems/selenium-webdriver-3.3.0/lib/selenium/webdriver/remote/bridge.rb:120:in `get'
            from ~/.rvm/rubies/ruby-2.4.0/lib/ruby/gems/2.4.0/gems/selenium-webdriver-3.3.0/lib/selenium/webdriver/common/navigation.rb:32:in `to'
            from (irb):4
            from ~/.rvm/rubies/ruby-2.4.0/bin/irb:11:in `<main>'
    irb(main):005:0> exit

最终，我想使用 Capybara 运行可以在我的设置中运行的系统测试（开发机器 = 操作系统 = Linux Ubuntu 的虚拟机，通过 PuTTY 远程访问）。

我找到了一种让它发挥作用的方法。

为此，我放弃了 Chrome 及其 Selenium 驱动程序，转而使用 PhantomJS 和 poltergeist。

PhantomJS 是一个无头浏览器（= 无 GUI）。效果很好。这是我的步骤（Rails 5.1）：

1. 将 gem 'poltergeist' 添加到您的 Gemfile 中，并注释掉 gem 'selenium-webdriver' （后者是 chrome 需要的，我们不会使用它）：

   #gem 'selenium-webdriver'
   gem 'poltergeist'
   

2. Run bundle update

3. 添加 poltergeist 驱动程序配置（在文件中application_system_test_case.rb），注释掉 chrome 驱动配置：

   $ cat test/application_system_test_case.rb
   
   require "test_helper"
   
   require "capybara/poltergeist"
   Capybara.javascript_driver = :poltergeist      
   
   class ApplicationSystemTestCase < ActionDispatch::SystemTestCase
     # driven_by :selenium, using: :chrome, screen_size: [1400, 1400]
     driven_by :poltergeist
   end
   

4. 下载“PhantomJS”无头浏览器，并将其放在 PATH 中的目录中：

   $ wget https://bitbucket.org/ariya/phantomjs/downloads/phantomjs-1.9.8-linux-x86_64.tar.bz2
   $ tar -xjvf phantomjs-1.9.8-linux-x86_64.tar.bz2
   $ sudo cp phantomjs-1.9.8-linux-x86_64/bin/phantomjs /usr/local/bin
   $ sudo chmod +x /usr/local/bin/phantomjs
   

5. 您已准备就绪，可以运行系统测试了。例如：

   $ rake test TEST=test/system/posts_test.rb
   Run options: --seed 38196
   
   # Running:
   
   Puma starting in single mode...
   * Version 3.8.2 (ruby 2.4.0-p0), codename: Sassy Salamander
   * Min threads: 0, max threads: 1
   * Environment: test
   * Listening on tcp://0.0.0.0:44265
   Use Ctrl-C to stop
   You're running an old version of PhantomJS, update to >= 2.1.1 for a better experience.
   .
   
   Finished in 1.366478s, 0.7318 runs/s, 0.7318 assertions/s.
   
   1 runs, 1 assertions, 0 failures, 0 errors, 0 skips
   $