Skip show commands for doc tests

skimage/io/_io.py

@@ -248,7 +248,7 @@ def show():
 
     >>> for i in range(4):
     ...     io.imshow(np.random.random((50, 50)))
-    >>> io.show()
+    >>> io.show() # doctest: +SKIP
 
     '''
     return call_plugin('_app_show')

skimage/viewer/viewers/core.py

@@ -73,7 +73,7 @@ class ImageViewer(QtGui.QMainWindow):
     >>> from skimage import data
     >>> image = data.coins()
     >>> viewer = ImageViewer(image)
-    >>> # viewer.show()
+    >>> viewer.show() # doctest: +SKIP
 
     """