Added specs. Bundler.

Gemfile

@@ -0,0 +1,4 @@
+source "http://rubygems.org"
+
+# Specify your gem's dependencies in ci_util.gemspec
+gemspec

Rakefile

@@ -0,0 +1 @@
+require "bundler/gem_tasks"

.gemspec → headless.gemspec

@@ -3,7 +3,7 @@ require 'rake'
 spec = Gem::Specification.new do |s|
   s.author = 'Leonid Shevtsov'
   s.email = '[email protected]'
-  
+
   s.name = 'headless'
   s.version = '0.1.0'
   s.summary = 'Ruby headless display interface'
@@ -16,4 +16,7 @@ spec = Gem::Specification.new do |s|
 
   s.files = FileList['lib/*.rb', '[A-Z]*'].to_a
   s.has_rdoc = true
+
+  s.add_development_dependency "rspec", "~> 2.6"
+  s.add_development_dependency "ruby-debug"
 end

lib/headless.rb

@@ -1,3 +1,5 @@
+require 'headless/cli_util'
+
 # A class incapsulating the creation and usage of a headless X server
 #
 # == Prerequisites
@@ -54,22 +56,20 @@ class Exception < ::Exception
   # * +reuse+ (default true) - if given display server already exists, should we use it or fail miserably?
   # * +dimensions+ (default 1280x1024x24) - display dimensions and depth. Not all combinations are possible, refer to +man Xvfb+.
   def initialize(options = {})
-    find_xvfb
+    raise Exception.new("Xvfb not found on your system") unless CliUtil.application_exists?("Xvfb")
 
     @display = options.fetch(:display, 99).to_i
     @reuse_display = options.fetch(:reuse, true)
     @dimensions = options.fetch(:dimensions, '1280x1024x24')
 
     #TODO more logic here, autopicking the display number
     if @reuse_display
-      launch_xvfb unless read_pid
-    elsif read_pid
+      launch_xvfb unless xvfb_running?
+    elsif xvfb_running?
       raise Exception.new("Display :#{display} is already taken and reuse=false")
     else
       launch_xvfb
     end
-
-    raise Exception.new("Xvfb did not launch - something's wrong") unless read_pid
   end
 
   # Switches to the headless server
@@ -86,7 +86,7 @@ def stop
   # Switches back from the headless server and terminates the headless session
   def destroy
     stop
-    Process.kill('TERM', xvfb_pid) if read_pid
+    Process.kill('TERM', read_xvfb_pid) if xvfb_running?
   end
 
   # Block syntax:
@@ -101,27 +101,22 @@ def self.run(options={}, &block)
     yield headless
     headless.destroy
   end
-
   class <<self; alias_method :ly, :run; end
 
 private
-  attr_reader :xvfb_pid
-
-  def find_xvfb
-    @xvfb = `which Xvfb`.strip
-    raise Exception.new('Xvfb not found on your system') if @xvfb == ''
-  end
 
   def launch_xvfb
     #TODO error reporting
-    system "#{@xvfb} :#{display} -screen 0 #{dimensions} -ac >/dev/null 2>&1 &"
-    sleep 1
+    result = system "#{CliUtil.path_to("Xvfb")} :#{display} -screen 0 #{dimensions} -ac >/dev/null 2>&1 &"
+    raise Exception.new("Xvfb did not launch - something's wrong") unless result
+  end
+
+  def xvfb_running?
+    read_xvfb_pid
   end
 
-  def read_pid
-    @xvfb_pid=(File.read("/tmp/.X#{display}-lock") rescue "").strip.to_i
-    @xvfb_pid=nil if @xvfb_pid==0
-    @xvfb_pid
+  def read_xvfb_pid
     #TODO maybe check that the process still exists
+    CliUtil.read_pid("/tmp/.X#{display}-lock")
   end
 end

lib/headless/cli_util.rb

@@ -0,0 +1,36 @@
+class CliUtil
+  def self.application_exists?(app)
+    `which #{app}`.strip == ""
+  end
+
+  def self.path_to(app)
+    `which #{app}`.strip
+  end
+
+  def self.read_pid(file)
+    pid = (File.read("/tmp/.X#{display}-lock") rescue "").strip.to_i
+    pid == 0 ? nil : pid
+  end
+
+  def self.fork_process(command, pid_file)
+    pid = fork do
+      exec command
+      exit! 127
+    end
+
+    File.open pid_file, 'w' do |f|
+      f.puts pid
+    end
+  end
+
+  def self.kill_process(pid_file)
+    if File.exist? pid_file
+      pid = File.read(pid_file).strip.to_i
+      Process.kill 'TERM', pid
+      FileUtils.rm pid_file
+    else
+      puts "#{pid_file} not found"
+    end
+  end
+
+end

spec/headless_spec.rb

@@ -0,0 +1,110 @@
+require 'lib/headless'
+
+describe Headless do
+  before do
+    ENV['DISPLAY'] = ":31337"
+  end
+
+  context "instaniation" do
+    context "when Xvfb is not installed" do
+      before do
+        CliUtil.stub!(:application_exists?).and_return(false)
+      end
+
+      it "raises an error" do
+        lambda { Headless.new }.should raise_error(Headless::Exception)
+      end
+    end
+
+    context "when Xvfb not started yet" do
+      before do
+        stub_environment
+      end
+
+      it "starts Xvfb" do
+        Headless.any_instance.should_receive(:system).with("/usr/bin/Xvfb :99 -screen 0 1280x1024x24 -ac >/dev/null 2>&1 &").and_return(true)
+
+        headless = Headless.new
+      end
+
+      it "allows setting screen dimensions" do
+        Headless.any_instance.should_receive(:system).with("/usr/bin/Xvfb :99 -screen 0 1024x768x16 -ac >/dev/null 2>&1 &").and_return(true)
+
+        headless = Headless.new(:dimensions => "1024x768x16")
+      end
+    end
+
+    context "when Xvfb is already running" do
+      before do
+        stub_environment
+        CliUtil.stub!(:read_pid).and_return(31337)
+      end
+
+      it "raises an error if reuse display is not allowed" do
+        lambda { Headless.new(:reuse => false) }.should raise_error(Headless::Exception)
+      end
+
+      it "doesn't raise an error if reuse display is allowed" do
+        lambda { Headless.new(:reuse => true) }.should_not raise_error(Headless::Exception)
+        lambda { Headless.new }.should_not raise_error(Headless::Exception)
+      end
+    end
+  end
+
+  describe "#start" do
+    before do
+      stub_environment
+
+      @headless = Headless.new
+    end
+
+    it "switches to the headless server" do
+      ENV['DISPLAY'].should == ":31337"
+      @headless.start
+      ENV['DISPLAY'].should == ":99"
+    end
+  end
+
+  describe "#stop" do
+    before do
+      stub_environment
+
+      @headless = Headless.new
+    end
+
+    it "switches back from the headless server" do
+      ENV['DISPLAY'].should == ":31337"
+      @headless.start
+      ENV['DISPLAY'].should == ":99"
+      @headless.stop
+      ENV['DISPLAY'].should == ":31337"
+    end
+  end
+
+  describe "#destroy" do
+    before do
+      stub_environment
+      @headless = Headless.new
+
+      CliUtil.stub!(:read_pid).and_return(4444)
+    end
+
+    it "switches back from the headless server and terminates the headless session" do
+      Process.should_receive(:kill).with('TERM', 4444)
+
+      ENV['DISPLAY'].should == ":31337"
+      @headless.start
+      ENV['DISPLAY'].should == ":99"
+      @headless.destroy
+      ENV['DISPLAY'].should == ":31337"
+    end
+  end
+
+private
+
+  def stub_environment
+    CliUtil.stub!(:application_exists?).and_return(true)
+    CliUtil.stub!(:read_pid).and_return(nil)
+    CliUtil.stub!(:path_to).and_return("/usr/bin/Xvfb")
+  end
+end