Corrected stubbing of root function

Signed-off-by: Tom Van Herreweghe <tom@king-foo.be>

Author: Tom Van Herreweghe

tests/PHPExif/Adapter/ExiftoolProcOpenTest.php

@@ -1,14 +1,28 @@
 <?php
+// disable the mock by default
+namespace
+{  
+    $mockProcOpen = false;
+}  
 
-namespace PHPExif\Tests\Adapter {
+// same namespace as SUT
+namespace PHPExif\Adapter
+{
 
-    function proc_open()
+    // stub the function
+    function proc_open($cmd, array $descriptorspec , &$pipes = array())
     {
+        global $mockProcOpen;
+        if (isset($mockProcOpen) && !$mockProcOpen) {
+            return \proc_open(
+                $cmd,
+                $descriptorspec,
+                $pipes
+            );
+        }
         return false;
     }
 
-    include __DIR__ . '/../../../lib/PHPExif/Adapter/Exiftool.php';
-
     /**
      * @covers \PHPExif\Adapter\Exiftool::<!public>
      */
@@ -21,11 +35,21 @@ class ExiftoolProcOpenTest extends \PHPUnit_Framework_TestCase
 
         public function setUp()
         {
+            global $mockProcOpen;
+            $mockProcOpen = true;
             $this->adapter = new \PHPExif\Adapter\Exiftool();
         }
+
+        public function tearDown()
+        {
+            global $mockProcOpen;
+            $mockProcOpen = false;
+        }
+
         /**
          * @group exiftool
          * @covers \PHPExif\Adapter\Exiftool::getCliOutput
+         * @expectedException RuntimeException
          */
         public function testGetCliOutput()
         {
@@ -39,8 +63,6 @@ public function testGetCliOutput()
                     'pwd'
                 )
             );
-
-            $this->assertInternalType('string', $result);
         }
     }
 }