There is a problem with the way that acts_as_ferret verifies the index
is valid. In ensure_index_exists it looks for a file named ‘segments’.
With the 0.11.0 release of ferret there is no file with this name. On my
dummy application I have a ‘segments.gen’ and ‘segments_2y’.
Changing the test to segments.gen fixes the problem that the index is
constantly rebuilt. I don’t know enough about these files to know if
this is a good fix or now.