Ensure that the PhantomJS command executes successfully (#71)

* Ensure that the PhantomJS command executes successfully

* Validate on return code instead of anything was in the output

Author: mbardelmeijer

src/Capture.php

@@ -3,6 +3,7 @@
 namespace Screen;
 
 use Screen\Exceptions\InvalidArgumentException;
+use Screen\Exceptions\PhantomJsException;
 use Screen\Exceptions\TemplateNotFoundException;
 use Screen\Image\Types;
 use Screen\Image\Types\Type;
@@ -225,7 +226,15 @@ public function save($imageLocation, $deleteFileIfExists = true)
         }
 
         $command = sprintf("%sphantomjs %s %s", $this->binPath, $this->getOptionsString(), $jobPath);
-        $result = exec(escapeshellcmd($command));
+
+        // Run the command and ensure it executes successfully
+        $returnCode = null;
+        $output = [];
+        exec(sprintf("%s 2>&1", escapeshellcmd($command)), $output, $returnCode);
+
+        if ($returnCode !== 0) {
+            throw new PhantomJsException($output);
+        }
 
         return file_exists($this->imageLocation);
     }

src/Exceptions/PhantomJsException.php

@@ -0,0 +1,13 @@
+<?php
+
+namespace Screen\Exceptions;
+
+class PhantomJsException extends \Exception
+{
+    public function __construct($message, $code = 0, \Exception $previous = null)
+    {
+        $message = is_array($message) ? implode(PHP_EOL, $message) : $message;
+
+        parent::__construct($message, $code, $previous);
+    }
+}