Update multi_image test and install tifffile for travis.

skimage/io/tests/test_multi_image.py

@@ -1,19 +1,11 @@
 import os
 
 import numpy as np
-from numpy.testing.decorators import skipif
 from numpy.testing import assert_raises, assert_equal, assert_allclose
 
 from skimage import data_dir
 from skimage.io.collection import MultiImage
 
-try:
-    from PIL import Image
-except ImportError:
-    PIL_available = False
-else:
-    PIL_available = True
-
 import six
 
 
@@ -22,14 +14,11 @@ class TestMultiImage():
     def setUp(self):
         # This multipage TIF file was created with imagemagick:
         # convert im1.tif im2.tif -adjoin multipage.tif
-        if PIL_available:
-            self.img = MultiImage(os.path.join(data_dir, 'multipage.tif'))
+        self.img = MultiImage(os.path.join(data_dir, 'multipage.tif'))
 
-    @skipif(not PIL_available)
     def test_len(self):
         assert len(self.img) == 2
 
-    @skipif(not PIL_available)
     def test_getitem(self):
         num = len(self.img)
         for i in range(-num, num):
@@ -42,7 +31,6 @@ class TestMultiImage():
         assert_raises(IndexError, return_img, num)
         assert_raises(IndexError, return_img, -num - 1)
 
-    @skipif(not PIL_available)
     def test_files_property(self):
         assert isinstance(self.img.filename, six.string_types)
 
@@ -50,7 +38,6 @@ class TestMultiImage():
             self.img.filename = f
         assert_raises(AttributeError, set_filename, 'newfile')
 
-    @skipif(not PIL_available)
     def test_conserve_memory_property(self):
         assert isinstance(self.img.conserve_memory, bool)
 
@@ -58,7 +45,6 @@ class TestMultiImage():
             self.img.conserve_memory = val
         assert_raises(AttributeError, set_mem, True)
 
-    @skipif(not PIL_available)
     def test_concatenate(self):
         array = self.img.concatenate()
         assert_equal(array.shape, (len(self.img),) + self.img[0].shape)