More GIMP palette tests

Tests/images/bad_palette_entry.gpl

@@ -0,0 +1,12 @@
+GIMP Palette
+Name: badpaletteentry
+Columns: 4
+#
+  0   0   0     Index 3
+ 65  38
+103  62  49     Index 6
+ 79  73  72     Index 7
+114 101  97     Index 8
+208 127 100     Index 9
+151 144 142     Index 10
+221 207 199     Index 11

Tests/images/bad_palette_file.gpl

@@ -0,0 +1,12 @@
+GIMP Palette
+Name: badpalettefile
+Columns: 4
+#
+  0   0   0     Index 3
+01234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789
+103  62  49     Index 6
+ 79  73  72     Index 7
+114 101  97     Index 8
+208 127 100     Index 9
+151 144 142     Index 10
+221 207 199     Index 11

Tests/images/custom_gimp_palette.gpl

@@ -0,0 +1,12 @@
+GIMP Palette
+Name: custompalette
+Columns: 4
+#
+  0   0   0     Index 3
+ 65  38  30     Index 4
+103  62  49     Index 6
+ 79  73  72     Index 7
+114 101  97     Index 8
+208 127 100     Index 9
+151 144 142     Index 10
+221 207 199     Index 11

Tests/test_file_gimppalette.py

@@ -12,6 +12,23 @@ class TestImage(PillowTestCase):
         with open('Tests/images/hopper.jpg', 'rb') as fp:
             self.assertRaises(SyntaxError, lambda: GimpPaletteFile(fp))
 
+        with open('Tests/images/bad_palette_file.gpl', 'rb') as fp:
+            self.assertRaises(SyntaxError, lambda: GimpPaletteFile(fp))
+
+        with open('Tests/images/bad_palette_entry.gpl', 'rb') as fp:
+            self.assertRaises(ValueError, lambda: GimpPaletteFile(fp))
+
+    def test_get_palette(self):
+        # Arrange
+        with open('Tests/images/custom_gimp_palette.gpl', 'rb') as fp:
+            palette_file = GimpPaletteFile(fp)
+
+        # Act
+        palette, mode = palette_file.getpalette()
+
+        # Assert
+        self.assertEqual(mode, "RGB")
+
 
 if __name__ == '__main__':
     unittest.main()