>># 
>># Copyright 1990, 1991 by the Massachusetts Institute of Technology and
>># UniSoft Group Limited.
>># 
>># Permission to use, copy, modify, distribute, and sell this software and
>># its documentation for any purpose is hereby granted without fee,
>># provided that the above copyright notice appear in all copies and that
>># both that copyright notice and this permission notice appear in
>># supporting documentation, and that the names of MIT and UniSoft not be
>># used in advertising or publicity pertaining to distribution of the
>># software without specific, written prior permission.  MIT and UniSoft
>># make no representations about the suitability of this software for any
>># purpose.  It is provided "as is" without express or implied warranty.
>># 
>># $XConsortium: emptyrgn.m,v 1.7 92/06/11 17:34:10 rws Exp $
>># 
>>#
>>TITLE XEmptyRegion CH10
>>ASSERTION A XEmptyRegion-1
When the region r is empty, then a call to XEmptyRegion
returns True.
>>STRATEGY
Create a region using XCreateRegion.
Verify that the region is empty using XEmptyRegion.
Compute the intersection of two disjoint regions.
Verify that the region is empty using XEmptyRegion.
>>ASSERTION A XEmptyRegion-2
When the region r is not empty, then a call to XEmptyRegion
returns False.
>>STRATEGY
Create a region using XCreateRegion.
Set the region using XUnionRectWithRegion.
Verify that the region is non-empty using XEmptyRegion.
