From 495e415c25d14935b3ab059eb124ab2ab1072007 Mon Sep 17 00:00:00 2001
From: Oliver Vogel <oliver@olivervogel.net>
Date: Tue, 18 Mar 2014 18:57:12 +0100
Subject: [PATCH] added ImageBackupNotAvailableException

---
 .../Image/Exception/ImageBackupNotAvailableException.php | 8 ++++++++
 src/Intervention/Image/Image.php                         | 2 ++
 tests/ImageTest.php                                      | 9 +++++++++
 3 files changed, 19 insertions(+)
 create mode 100644 src/Intervention/Image/Exception/ImageBackupNotAvailableException.php

diff --git a/src/Intervention/Image/Exception/ImageBackupNotAvailableException.php b/src/Intervention/Image/Exception/ImageBackupNotAvailableException.php
new file mode 100644
index 00000000..1b9c7214
--- /dev/null
+++ b/src/Intervention/Image/Exception/ImageBackupNotAvailableException.php
@@ -0,0 +1,8 @@
+<?php
+
+namespace Intervention\Image\Exception;
+
+class ImageBackupNotAvailableException extends \RuntimeException
+{
+    # nothing to override
+}
diff --git a/src/Intervention/Image/Image.php b/src/Intervention/Image/Image.php
index 56209b1a..da6b5389 100644
--- a/src/Intervention/Image/Image.php
+++ b/src/Intervention/Image/Image.php
@@ -1469,6 +1469,8 @@ class Image
         if ($this->isImageResource($this->original)) {
             is_resource($this->resource) ? imagedestroy($this->resource) : null;
             $this->initFromResource($this->original);
+        } else {
+            throw new Exception\ImageBackupNotAvailableException('backup() must be called first to use reset().');
         }
 
         return $this;
diff --git a/tests/ImageTest.php b/tests/ImageTest.php
index 61330ef5..eb4c602c 100644
--- a/tests/ImageTest.php
+++ b/tests/ImageTest.php
@@ -1419,6 +1419,15 @@ class ImageTest extends PHPUnit_Framework_Testcase
         $this->assertEquals('#0000ff', $img->pickColor(0, 0, 'hex'));
     }
 
+    /**
+     * @expectedException Intervention\Image\Exception\ImageBackupNotAvailableException
+     */
+    public function testResetImageWithoutBackup()
+    {
+        $img = $this->getTestImage();
+        $img->reset();
+    }
+
     public function testBackup()
     {
         $img = new Image(null, 800, 600, '#0000ff');