* integration tests

* More informative error messages
* If video recorder provider is libav, use avconv binary instead of ffmpeg
* Rewritten Xvfb launch using Process.spawn and avoiding a shell
* Do not manually remove X11 lock file when stopping Xvfb; this isn’t conventional. Should eliminate some errors with not being able to find Xvfb
* Detect situation when Xvfb can’t listen to any sockets and raise corresponding error
* Properly working integration tests

Author: leonid-shevtsov

.travis.yml

@@ -2,5 +2,8 @@ language: ruby
 rvm:
   - 1.9.3
   - 2.0
-  - 2.1
+  - 2.2
+before_install:
+  - "sudo apt-get update"
+  - "sudo apt-get install -y firefox xvfb libav-tools"
 script: "rspec"

headless.gemspec

@@ -16,4 +16,5 @@ spec = Gem::Specification.new do |s|
 
   s.add_development_dependency 'rake'
   s.add_development_dependency "rspec", "~> 3"
+  s.add_development_dependency "selenium-webdriver"
 end

lib/headless.rb

@@ -103,7 +103,13 @@ def stop
   # Switches back from the headless server and terminates the headless session
   def destroy
     stop
-    CliUtil.kill_process(pid_filename)
+    CliUtil.kill_process(pid_filename, preserve_pid_file: true)
+  end
+
+  # Same as destroy, but waits for Xvfb process to terminate
+  def destroy_sync
+    stop
+    CliUtil.kill_process(pid_filename, preserve_pid_file: true, wait: true)
   end
 
   # Block syntax:
@@ -159,18 +165,30 @@ def pick_available_display(display_set, can_reuse)
   end
 
   def launch_xvfb
-    #TODO error reporting
-    result = system "#{CliUtil.path_to("Xvfb")} :#{display} -screen 0 #{dimensions} -ac >/dev/null 2>&1 &"
-    raise Headless::Exception.new("Xvfb did not launch - something's wrong") unless result
-    ensure_xvfb_is_running
+    out_pipe, in_pipe = IO.pipe
+    pid = Process.spawn(
+      CliUtil.path_to("Xvfb"), ":#{display}", "-screen", "0", dimensions, "-ac",
+      err: in_pipe)
+    in_pipe.close
+    raise Headless::Exception.new("Xvfb did not launch - something's wrong") unless pid
+    ensure_xvfb_is_running(out_pipe)
     return true
   end
 
-  def ensure_xvfb_is_running
+  def ensure_xvfb_is_running(out_pipe)
     start_time = Time.now
+    errors = ""
     begin
+      begin
+        errors += out_pipe.read_nonblock(10000)
+        if errors.include? "Cannot establish any listening sockets"
+          raise Headless::Exception.new("Display socket is taken but lock file is missing - check the Headless troubleshooting guide")
+        end
+      rescue IO::WaitReadable
+        # will retry next cycle
+      end
       sleep 0.01 # to avoid cpu hogging
-      raise Headless::Exception.new("Xvfb is frozen") if (Time.now-start_time)>=@xvfb_launch_timeout
+      raise Headless::Exception.new("Xvfb launched but did not complete initialization") if (Time.now-start_time)>=@xvfb_launch_timeout
     end while !xvfb_running?
   end
 
@@ -197,4 +215,3 @@ def hook_at_exit
     end
   end
 end
-

lib/headless/cli_util.rb

@@ -53,11 +53,13 @@ def self.kill_process(pid_filename, options={})
           # Process.wait tried to wait on a dead process
         end
       end
-      
-      begin
-        FileUtils.rm pid_filename
-      rescue Errno::ENOENT
-        # pid file already removed
+
+      unless options[:preserve_pid_file]
+        begin
+          FileUtils.rm pid_filename
+        rescue Errno::ENOENT
+          # pid file already removed
+        end
       end
     end
   end

lib/headless/video/video_recorder.rb

@@ -5,8 +5,6 @@ class VideoRecorder
     attr_accessor :pid_file_path, :tmp_file_path, :log_file_path
 
     def initialize(display, dimensions, options = {})
-      CliUtil.ensure_application_exists!('ffmpeg', 'Ffmpeg not found on your system. Install it with sudo apt-get install ffmpeg')
-
       @display = display
       @dimensions = dimensions[/.+(?=x)/]
 
@@ -17,33 +15,14 @@ def initialize(display, dimensions, options = {})
       @frame_rate = options.fetch(:frame_rate, 30)
       @provider = options.fetch(:provider, :libav)  # or :ffmpeg
       @extra = Array(options.fetch(:extra, []))
+
+      CliUtil.ensure_application_exists!(provider_binary, "#{provider_binary} not found on your system. Install it or change video recorder provider")
     end
 
     def capture_running?
       CliUtil.read_pid @pid_file_path
     end
 
-    def command_line_for_capture
-      if @provider == :libav
-        group_of_pic_size_option = '-g 600'
-        dimensions = @dimensions
-      else
-        group_of_pic_size_option = nil
-        dimensions = @dimensions.match(/^(\d+x\d+)/)[0]
-      end
-
-      ([
-        CliUtil.path_to('ffmpeg'),
-        "-y",
-        "-r #{@frame_rate}",
-        "-s #{dimensions}",
-        "-f x11grab",
-        "-i :#{@display}",
-        group_of_pic_size_option,
-        "-vcodec #{@codec}"
-      ].compact + @extra + [@tmp_file_path]).join(' ')
-    end
-
     def start_capture
       CliUtil.fork_process(command_line_for_capture,
                            @pid_file_path, @log_file_path)
@@ -73,5 +52,32 @@ def stop_and_discard
         # that's ok if the file doesn't exist
       end
     end
+
+    private
+
+    def provider_binary
+      @provider==:libav ? 'avconv' : 'ffmpeg'
+    end
+
+    def command_line_for_capture
+      if @provider == :libav
+        group_of_pic_size_option = '-g 600'
+        dimensions = @dimensions
+      else
+        group_of_pic_size_option = nil
+        dimensions = @dimensions.match(/^(\d+x\d+)/)[0]
+      end
+
+      ([
+        CliUtil.path_to(provider_binary),
+        "-y",
+        "-r #{@frame_rate}",
+        "-s #{dimensions}",
+        "-f x11grab",
+        "-i :#{@display}",
+        group_of_pic_size_option,
+        "-vcodec #{@codec}"
+      ].compact + @extra + [@tmp_file_path]).join(' ')
+    end
   end
 end