Ensure PIL tests run with PIL.

skimage/io/tests/test_io.py

@@ -1,8 +1,7 @@
 import os
 
-from numpy.testing import *
+from numpy.testing import assert_array_equal, raises, run_module_suite
 import numpy as np
-from StringIO import StringIO
 
 import skimage.io as io
 from skimage import data_dir
@@ -29,20 +28,5 @@ def test_imread_url():
     assert image.shape == (512, 512)
 
 
-def test_imsave_filelike():
-    shape = (2, 2)
-    image = np.zeros(shape)
-    s = StringIO()
-
-    # save to file-like object
-    io.imsave(s, image)
-
-    # read from file-like object
-    s.seek(0)
-    out = io.imread(s)
-    assert out.shape == shape
-    np.testing.assert_allclose(out, image)
-
-
 if __name__ == "__main__":
     run_module_suite()

skimage/io/tests/test_pil.py

@@ -7,6 +7,8 @@ from tempfile import NamedTemporaryFile
 
 from skimage import data_dir
 from skimage.io import imread, imsave, use_plugin, reset_plugins
+from skimage._shared.six.moves import StringIO
+
 
 try:
     from PIL import Image
@@ -124,5 +126,22 @@ class TestSave:
                     x = (x * 255).astype(dtype)
                     yield self.roundtrip, dtype, x
 
+
+@skipif(not PIL_available)
+def test_imsave_filelike():
+    shape = (2, 2)
+    image = np.zeros(shape)
+    s = StringIO()
+
+    # save to file-like object
+    imsave(s, image)
+
+    # read from file-like object
+    s.seek(0)
+    out = imread(s)
+    assert out.shape == shape
+    assert_allclose(out, image)
+
+
 if __name__ == "__main__":
     run_module_suite()