Tests and partial implementation of pickling (#629)

PIL/Image.py

@@ -568,6 +568,15 @@ class Image:
             return new
         raise AttributeError(name)
 
+    def __getstate__(self):
+        return [self.mode, self.size, self.tobytes()]
+
+    def __setstate__(self, state):
+        mode, size, data = state
+        self.mode = mode
+        self.size = size
+        self.frombytes(data)
+
     def tobytes(self, encoder_name="raw", *args):
         """
         Return image as a bytes object

Tests/test_pickle.py

@@ -0,0 +1,63 @@
+from tester import *
+
+from PIL import Image
+
+
+def test_frombytes_tobytes():
+    # Arrange
+    im = Image.open('Images/lena.jpg')
+
+    # Act
+    data = im.tobytes()
+    new_im = Image.frombytes(im.mode, im.size, data)
+
+    # Assert
+    assert_image_equal(im, new_im)
+
+
+def helper_test_pickle_file(pickle, protocol=0):
+    im = Image.open('Images/lena.jpg')
+    filename = tempfile('temp.pkl')
+
+    # Act
+    with open(filename, 'wb') as f:
+        pickle.dump(im, f, protocol)
+    with open(filename, 'rb') as f:
+        loaded_im = pickle.load(f)
+
+    # Assert
+    assert_image_equal(im, loaded_im)
+
+
+def helper_test_pickle_string(pickle, protocol=0):
+    im = Image.open('Images/lena.jpg')
+
+    # Act
+    dumped_string = pickle.dumps(im, protocol)
+    loaded_im = pickle.loads(dumped_string)
+
+    # Assert
+    assert_image_equal(im, loaded_im)
+
+
+def test_pickle_image():
+    # Arrange
+    import pickle
+
+    # Act / Assert
+    for protocol in range(0, pickle.HIGHEST_PROTOCOL + 1):
+        helper_test_pickle_string(pickle, protocol)
+        helper_test_pickle_file(pickle, protocol)
+
+
+def test_cpickle_image():
+    # Arrange
+    import cPickle
+
+    # Act / Assert
+    for protocol in range(0, cPickle.HIGHEST_PROTOCOL + 1):
+        helper_test_pickle_string(cPickle, protocol)
+        helper_test_pickle_file(cPickle, protocol)
+
+
+# End of file