Where to put a Calc unit test

Hi all,

I'm working on bug tdf#103092. The error is, that Calc interprets the 
measure unit from registrymodifications.xcu wrongly and therefore writes 
for a transformed shape a wrong unit in the draw:transform attribute, 
which results in a wrong position of the shape after reopening the file.

The error is specific for Calc. In a unit test I need to open a 
document, change the setting in registrymodifications.xcu, save the file 
and reopen it, then examine the shape position.

Where should I put such unit test?

Kind regards
Regina