diff --git a/src/Symfony/Component/Process/ExecutableFinder.php b/src/Symfony/Component/Process/ExecutableFinder.php
index 087c94b0f2..5cc99c7692 100644
--- a/src/Symfony/Component/Process/ExecutableFinder.php
+++ b/src/Symfony/Component/Process/ExecutableFinder.php
@@ -19,22 +19,23 @@ namespace Symfony\Component\Process;
  */
 class ExecutableFinder
 {
-    private static $isWindows;
-
     private $suffixes = array('.exe', '.bat', '.cmd', '.com');
 
-    public function __construct()
-    {
-        if (null === self::$isWindows) {
-            self::$isWindows = 0 === stripos(PHP_OS, 'win');
-        }
-    }
-
+    /**
+     * Replaces default suffixes of executable.
+     *
+     * @param array $suffixes
+     */
     public function setSuffixes(array $suffixes)
     {
         $this->suffixes = $suffixes;
     }
 
+    /**
+     * Adds new possible suffix to check for executable.
+     *
+     * @param string $suffix
+     */
     public function addSuffix($suffix)
     {
         $this->suffixes[] = $suffix;
@@ -78,7 +79,7 @@ class ExecutableFinder
         }
         foreach ($suffixes as $suffix) {
             foreach ($dirs as $dir) {
-                if (is_file($file = $dir.DIRECTORY_SEPARATOR.$name.$suffix) && (self::$isWindows || is_executable($file))) {
+                if (is_file($file = $dir.DIRECTORY_SEPARATOR.$name.$suffix) && (defined('PHP_WINDOWS_VERSION_BUILD') || is_executable($file))) {
                     return $file;
                 }
             }
diff --git a/src/Symfony/Component/Process/PhpProcess.php b/src/Symfony/Component/Process/PhpProcess.php
index 5db6e134e2..7a9fd0864b 100644
--- a/src/Symfony/Component/Process/PhpProcess.php
+++ b/src/Symfony/Component/Process/PhpProcess.php
@@ -66,6 +66,6 @@ class PhpProcess extends Process
             $this->setCommandLine($php);
         }
 
-        return parent::start($callback);
+        parent::start($callback);
     }
 }
diff --git a/src/Symfony/Component/Process/Process.php b/src/Symfony/Component/Process/Process.php
index 3ada4400e1..4af26e85a2 100644
--- a/src/Symfony/Component/Process/Process.php
+++ b/src/Symfony/Component/Process/Process.php
@@ -159,8 +159,8 @@ class Process
      * The STDOUT and STDERR are also available after the process is finished
      * via the getOutput() and getErrorOutput() methods.
      *
-     * @param Closure|string|array $callback A PHP callback to run whenever there is some
-     *                                       output available on STDOUT or STDERR
+     * @param callback|null $callback A PHP callback to run whenever there is some
+     *                                output available on STDOUT or STDERR
      *
      * @return integer The exit status code
      *
@@ -190,8 +190,8 @@ class Process
      * with true as a second parameter then the callback will get all data occurred
      * in (and since) the start call.
      *
-     * @param Closure|string|array $callback A PHP callback to run whenever there is some
-     *                                       output available on STDOUT or STDERR
+     * @param callback|null $callback A PHP callback to run whenever there is some
+     *                                output available on STDOUT or STDERR
      *
      * @throws \RuntimeException When process can't be launch or is stopped
      * @throws \RuntimeException When process is already running
@@ -318,11 +318,12 @@ class Process
      * from the output in real-time while writing the standard input to the process.
      * It allows to have feedback from the independent process during execution.
      *
-     * @param mixed $callback A valid PHP callback
+     * @param callback|null $callback A valid PHP callback
      *
-     * @return int The exitcode of the process
+     * @return integer The exitcode of the process
      *
-     * @throws \RuntimeException
+     * @throws \RuntimeException When process timed out
+     * @throws \RuntimeException When process stopped after receiving signal
      */
     public function wait($callback = null)
     {
@@ -455,8 +456,6 @@ class Process
      *
      * @return string A string representation for the exit status code
      *
-     * @throws RuntimeException In case --enable-sigchild is activated and the sigchild compatibility mode is disabled
-     *
      * @see http://tldp.org/LDP/abs/html/exitcodes.html
      * @see http://en.wikipedia.org/wiki/Unix_signal
      */
@@ -472,8 +471,6 @@ class Process
      *
      * @return Boolean true if the process ended successfully, false otherwise
      *
-     * @throws RuntimeException In case --enable-sigchild is activated and the sigchild compatibility mode is disabled
-     *
      * @api
      */
     public function isSuccessful()
@@ -576,11 +573,9 @@ class Process
     /**
      * Stops the process.
      *
-     * @param float $timeout The timeout in seconds
+     * @param integer|float $timeout The timeout in seconds
      *
      * @return integer The exit-code of the process
-     *
-     * @throws \RuntimeException if the process got signaled
      */
     public function stop($timeout=10)
     {
@@ -828,9 +823,9 @@ class Process
      * The callbacks adds all occurred output to the specific buffer and calls
      * the user callback (if present) with the received output.
      *
-     * @param mixed $callback The user defined PHP callback
+     * @param callback|null $callback The user defined PHP callback
      *
-     * @return mixed A PHP callable
+     * @return callback A PHP callable
      */
     protected function buildCallback($callback)
     {
@@ -870,6 +865,9 @@ class Process
         }
     }
 
+    /**
+     * Updates the current error output of the process (STDERR).
+     */
     protected function updateErrorOutput()
     {
         if (isset($this->pipes[self::STDERR]) && is_resource($this->pipes[self::STDERR])) {
@@ -877,6 +875,9 @@ class Process
         }
     }
 
+    /**
+     * Updates the current output of the process (STDOUT).
+     */
     protected function updateOutput()
     {
         if (defined('PHP_WINDOWS_VERSION_BUILD') && isset($this->fileHandles[self::STDOUT]) && is_resource($this->fileHandles[self::STDOUT])) {
diff --git a/src/Symfony/Component/Process/Tests/AbstractProcessTest.php b/src/Symfony/Component/Process/Tests/AbstractProcessTest.php
index 8cb9e4ad26..a5a3376f72 100644
--- a/src/Symfony/Component/Process/Tests/AbstractProcessTest.php
+++ b/src/Symfony/Component/Process/Tests/AbstractProcessTest.php
@@ -16,8 +16,6 @@ namespace Symfony\Component\Process\Tests;
  */
 abstract class AbstractProcessTest extends \PHPUnit_Framework_TestCase
 {
-    abstract protected function getProcess($commandline, $cwd = null, array $env = null, $stdin = null, $timeout = 60, array $options = array());
-
     /**
      * @expectedException \InvalidArgumentException
      */
@@ -300,4 +298,16 @@ abstract class AbstractProcessTest extends \PHPUnit_Framework_TestCase
 
         return $defaults;
     }
+
+    /**
+     * @param string  $commandline
+     * @param null    $cwd
+     * @param array   $env
+     * @param null    $stdin
+     * @param integer $timeout
+     * @param array   $options
+     *
+     * @return \Symfony\Component\Process\Process
+     */
+    abstract protected function getProcess($commandline, $cwd = null, array $env = null, $stdin = null, $timeout = 60, array $options = array());
 }
diff --git a/src/Symfony/Component/Process/Tests/SigchildDisabledProcessTest.php b/src/Symfony/Component/Process/Tests/SigchildDisabledProcessTest.php
index 4a321adf55..67fc0025bd 100644
--- a/src/Symfony/Component/Process/Tests/SigchildDisabledProcessTest.php
+++ b/src/Symfony/Component/Process/Tests/SigchildDisabledProcessTest.php
@@ -13,15 +13,6 @@ namespace Symfony\Component\Process\Tests;
 
 class SigchildDisabledProcessTest extends AbstractProcessTest
 {
-
-    protected function getProcess($commandline, $cwd = null, array $env = null, $stdin = null, $timeout = 60, array $options = array())
-    {
-        $process = new ProcessInSigchildEnvironment($commandline, $cwd, $env, $stdin, $timeout, $options);
-        $process->setEnhanceSigchildCompatibility(false);
-
-        return $process;
-    }
-
     /**
      * @expectedException Symfony\Component\Process\Exception\RuntimeException
      */
@@ -96,4 +87,15 @@ class SigchildDisabledProcessTest extends AbstractProcessTest
     {
         parent::testIsNotSuccessful();
     }
+
+    /**
+     * {@inheritdoc}
+     */
+    protected function getProcess($commandline, $cwd = null, array $env = null, $stdin = null, $timeout = 60, array $options = array())
+    {
+        $process = new ProcessInSigchildEnvironment($commandline, $cwd, $env, $stdin, $timeout, $options);
+        $process->setEnhanceSigchildCompatibility(false);
+
+        return $process;
+    }
 }
diff --git a/src/Symfony/Component/Process/Tests/SigchildEnabledProcessTest.php b/src/Symfony/Component/Process/Tests/SigchildEnabledProcessTest.php
index 4c04ff146b..fb9b6f8cc8 100644
--- a/src/Symfony/Component/Process/Tests/SigchildEnabledProcessTest.php
+++ b/src/Symfony/Component/Process/Tests/SigchildEnabledProcessTest.php
@@ -13,15 +13,6 @@ namespace Symfony\Component\Process\Tests;
 
 class SigchildEnabledProcessTest extends AbstractProcessTest
 {
-
-    protected function getProcess($commandline, $cwd = null, array $env = null, $stdin = null, $timeout = 60, array $options = array())
-    {
-        $process = new ProcessInSigchildEnvironment($commandline, $cwd, $env, $stdin, $timeout, $options);
-        $process->setEnhanceSigchildCompatibility(true);
-
-        return $process;
-    }
-
     /**
      * @expectedException Symfony\Component\Process\Exception\RuntimeException
      */
@@ -62,4 +53,14 @@ class SigchildEnabledProcessTest extends AbstractProcessTest
         $this->assertInternalType('string', $process->getExitCodeText());
     }
 
+    /**
+     * {@inheritdoc}
+     */
+    protected function getProcess($commandline, $cwd = null, array $env = null, $stdin = null, $timeout = 60, array $options = array())
+    {
+        $process = new ProcessInSigchildEnvironment($commandline, $cwd, $env, $stdin, $timeout, $options);
+        $process->setEnhanceSigchildCompatibility(true);
+
+        return $process;
+    }
 }
diff --git a/src/Symfony/Component/Process/Tests/SimpleProcessTest.php b/src/Symfony/Component/Process/Tests/SimpleProcessTest.php
index 8742a69e54..17dea3fe54 100644
--- a/src/Symfony/Component/Process/Tests/SimpleProcessTest.php
+++ b/src/Symfony/Component/Process/Tests/SimpleProcessTest.php
@@ -15,20 +15,14 @@ use Symfony\Component\Process\Process;
 
 class SimpleProcessTest extends AbstractProcessTest
 {
+    private $enabledSigchild = false;
 
-    protected function skipIfPHPSigchild()
+    public function setUp()
     {
         ob_start();
         phpinfo(INFO_GENERAL);
 
-        if (false !== strpos(ob_get_clean(), '--enable-sigchild')) {
-            $this->markTestSkipped('Your PHP has been compiled with --enable-sigchild, this test can not be executed');
-        }
-    }
-
-    protected function getProcess($commandline, $cwd = null, array $env = null, $stdin = null, $timeout = 60, array $options = array())
-    {
-        return new Process($commandline, $cwd, $env, $stdin, $timeout, $options);
+        $this->enabledSigchild = false !== strpos(ob_get_clean(), '--enable-sigchild');
     }
 
     public function testGetExitCode()
@@ -84,4 +78,19 @@ class SimpleProcessTest extends AbstractProcessTest
         $this->skipIfPHPSigchild();
         parent::testIsNotSuccessful();
     }
+
+    /**
+     * {@inheritdoc}
+     */
+    protected function getProcess($commandline, $cwd = null, array $env = null, $stdin = null, $timeout = 60, array $options = array())
+    {
+        return new Process($commandline, $cwd, $env, $stdin, $timeout, $options);
+    }
+
+    private function skipIfPHPSigchild()
+    {
+        if ($this->enabledSigchild) {
+            $this->markTestSkipped('Your PHP has been compiled with --enable-sigchild, this test can not be executed');
+        }
+    }
 }