Add tests for new behavior.

Add tests for new behavior

Fix utils import and make io.tests a package

skimage/io/_plugins/pil_plugin.py

@@ -29,7 +29,12 @@ def imread(fname, dtype=None):
 
 
     """
-    if fname.lower().endswith(('tif', 'tiff')) and dtype is None:
+    if hasattr(fname, 'name'):
+        name = fname.name.lower()
+    else:
+        name = fname.lower()
+
+    if name.endswith(('.tiff', '.tif')) and dtype is None:
         return tif_imread(fname)
 
     im = Image.open(fname)
@@ -104,18 +109,9 @@ def ndarray_to_pil(arr, format_str=None):
     Refer to ``imsave``.
 
     """
-    arr = np.asarray(arr).squeeze()
-
-    if arr.ndim not in (2, 3):
-        raise ValueError("Invalid shape for image array: %s" % arr.shape)
-
-    if arr.ndim == 3:
-        if arr.shape[2] not in (3, 4):
-            raise ValueError("Invalid number of channels in image array.")
-
     if arr.ndim == 3:
         arr = img_as_ubyte(arr)
-        mode_base = mode = {3: 'RGB', 4: 'RGBA'}[arr.shape[2]]
+        mode = {3: 'RGB', 4: 'RGBA'}[arr.shape[2]]
 
     elif arr.dtype.kind == 'f':
         arr = img_as_uint(arr)
@@ -137,8 +133,16 @@ def ndarray_to_pil(arr, format_str=None):
         mode = 'I'
         mode_base = 'I'
 
-    im = Image.new(mode_base, arr.T.shape)
-    im.fromstring(arr.tostring(), 'raw', mode)
+    if arr.ndim == 2:
+        im = Image.new(mode_base, arr.T.shape)
+        im.fromstring(arr.tostring(), 'raw', mode)
+    else:
+            try:
+                im = Image.frombytes(mode, (arr.shape[1], arr.shape[0]),
+                                      arr.tostring())
+            except AttributeError:
+                im = Image.fromstring(mode, (arr.shape[1], arr.shape[0]),
+                                       arr.tostring())
     return im
 
 
@@ -169,8 +173,25 @@ def imsave(fname, arr, format_str=None):
     if not isinstance(fname, string_types) and format_str is None:
         format_str = "PNG"
 
-    if fname.lower().endswith(('.tiff', '.tif')):
-        tif_imsave(fname)
+    if arr.ndim not in (2, 3):
+        raise ValueError("Invalid shape for image array: %s" % arr.shape)
+
+    if arr.ndim == 3:
+        if arr.shape[2] not in (3, 4):
+            raise ValueError("Invalid number of channels in image array.")
+
+    arr = np.asanyarray(arr).squeeze()
+
+    if arr.dtype.kind == 'b':
+        arr = arr.astype(np.uint8)
+
+    if hasattr(fname, 'name'):
+        name = fname.name.lower()
+    else:
+        name = fname.lower()
+
+    if name.endswith(('.tiff', '.tif')):
+        tif_imsave(fname, arr)
 
     else:
         img = ndarray_to_pil(arr, format_str=None)

skimage/io/tests/test_pil.py

@@ -8,6 +8,7 @@ from tempfile import NamedTemporaryFile
 from skimage import data_dir
 from skimage.io import (imread, imsave, use_plugin, reset_plugins,
                         Image as ioImage)
+from skimage.io.test.utils import ubyte_check, full_range_check
 
 from six import BytesIO
 
@@ -174,5 +175,17 @@ def test_imexport_imimport():
     assert out.shape == shape
 
 
+@skip(not PIL_available)
+def test_all_color(self):
+    ubyte_check('pil')
+    ubyte_check('pil', 'bmp')
+
+
+@skip(not PIL_available)
+def test_all_mono(self):
+    full_range_check('pil')
+    full_range_check('pil', 'tiff')
+
+
 if __name__ == "__main__":
     run_module_suite()

skimage/io/tests/utils.py

@@ -0,0 +1,82 @@
+from tempfile import NamedTemporaryFile
+
+from skimage import (
+    data, io, img_as_uint, img_as_bool, img_as_float, img_as_int, img_as_ubyte)
+from numpy import testing
+import numpy as np
+
+
+def roundtrip(img, plugin, suffix):
+    """Save and read an image using a specified plugin"""
+    if not '.' in suffix:
+        suffix = '.' + suffix
+    temp_file = NamedTemporaryFile(suffix=suffix, delete=False)
+    temp_file.close()
+    fname = temp_file.name
+    io.imsave(fname, img, plugin=plugin)
+    return io.imread(fname, plugin=plugin)
+
+
+def ubyte_check(plugin, fmt='png'):
+    """Check roundtrip behavior for images that can only be saved as uint8
+
+    All major input types should be handled as ubytes and read
+    back correctly.
+    """
+    img = img_as_ubyte(data.chelsea())
+    r1 = roundtrip(img, plugin, fmt)
+    testing.assert_allclose(img, r1)
+
+    img2 = img > 128
+    r2 = roundtrip(img2, plugin, fmt)
+    testing.assert_allclose(img2, img_as_bool(r2))
+
+    img3 = img_as_float(img)
+    r3 = roundtrip(img3, plugin, fmt)
+    testing.assert_allclose(r3, img)
+
+    img4 = img_as_int(img)
+    r4 = roundtrip(img4, plugin, fmt)
+    testing.assert_allclose(r4, img)
+
+    img5 = img_as_uint(img)
+    r5 = roundtrip(img5, plugin, fmt)
+    testing.assert_allclose(r5, img)
+
+
+def full_range_check(plugin, fmt='png'):
+    """Check the roundtrip behavior for images that support most types.
+
+    All major input types should be handled, except bool is treated
+    as ubyte and float can treated as uint16 or float.
+    """
+
+    img = img_as_ubyte(data.moon())
+    r1 = roundtrip(img, plugin, fmt)
+    testing.assert_allclose(img, r1)
+
+    img2 = img > 128
+    r2 = roundtrip(img2, plugin, fmt)
+    testing.assert_allclose(img2.astype(np.uint8), r2)
+
+    img3 = img_as_float(img)
+    r3 = roundtrip(img3, plugin, fmt)
+    if r3.dtype.kind == 'f':
+        testing.assert_allclose(img3, r3)
+    else:
+        testing.assert_allclose(r3, img_as_uint(img))
+
+    img4 = img_as_int(img)
+    r4 = roundtrip(img4, plugin, fmt)
+    testing.assert_allclose(r4, img4)
+
+    img5 = img_as_uint(img)
+    r5 = roundtrip(img5, plugin, fmt)
+    testing.assert_allclose(r5, img5)
+
+
+if __name__ == '__main__':
+    ubyte_check('pil')
+    full_range_check('pil')
+    ubyte_check('pil', 'bmp')
+    full_range_check('pil', 'tiff')