The test cases inside ltmWriter are being executed using the class
net.ontopia.topicmaps.utils.ltm.test.LTMTopicMapWriterTestGenerator.class.
This test suite is a bit complex, so here is a brief explanation of what each directory is for:

in        Contains normal input files.
ltm       LTM export directory for x-in.
          Ids should be preserved for all files in 'in'.
out       Canonicalization directory of files in 'ltm'.
baseline  Canonicalization directory of files in 'in'.

x-in        Like 'in', but for special cases.
x-ltm       LTM export directory for x-in
            NOTE: Topic map files in 'x-in' are to be exported preserving the
            ids, except the files starting with "generateId-", for which ids
            should be generated.
x-out       Canonicalization of files in x-ltm
x-baseline  Like baseline, but cannot be created automatically from source
            (needs manual intervention).
            
NOTE: The directories 'ltm', 'out', 'x-ltm' and 'x-out' are all autogenerated, 
and so are not checked into CVS.