Add test for palette_is_grayscale

scikits/image/io/pil_imread.py

@@ -1,4 +1,4 @@
-__all__ = ['imread']
+__all__ = ['imread', 'palette_is_grayscale']
 
 import numpy as np
 

scikits/image/io/tests/test_imread.py

@@ -2,7 +2,7 @@ import os.path
 import numpy as np
 
 from scikits.image import data_dir
-from scikits.image.io import imread
+from scikits.image.io import imread, palette_is_grayscale
 
 def test_imread_flatten():
     # a color image is flattened and returned as float32
@@ -21,3 +21,13 @@ def test_imread_palette():
     assert img.ndim == 2
     img = imread(os.path.join(data_dir, 'palette_color.png'))
     assert img.ndim == 3
+
+def test_palette_is_gray():
+    try:
+        from PIL import Image
+    except ImportError:
+        return
+    gray = Image.open(os.path.join(data_dir, 'palette_gray.png'))
+    assert palette_is_grayscale(gray)
+    color = Image.open(os.path.join(data_dir, 'palette_color.png'))
+    assert not palette_is_grayscale(color)