Mayavi test_extract_grid_filter.py

Mayavi/enthought/mayavi/tests/test_extract_grid_filter has two tests 
which examine the bounds of 3 different GridPlane objects as the 
attributes of the ExtractGrid object to which they are registered are 
modified. When the bounds of the GridPlane objects are retrieved (ie. 
gpx.actor.actor.bounds) all values in the tuple returned are less than 
the expected values by 100.

For instance, the first assert is the following:
self.assertEqual(allclose(gpx.actor.actor.bounds, (100.0, 100.0, 100.0, 
200.0, 100.0, 200.0)), True)

gpx.actor.actor.bounds returns:
(0.0, 0.0, 0.0, 100.0, 0.0, 100.0)

The same behavior described above applies to the rest of the 
actor.actor.bounds calls in the file. Is this due to an intentional 
change in Mayavi/tvtk or is this an error?

-David