I believe that Paddy was referencing his second point about keeping "production code" and "test code" clearly delimited, so was recommending that a version control system be used rather than the local disk structure required by python for building module packages.
Although, I have found that symlinks work fine for delimiting file structure - ex.: $BASEDIR/<production files> $TESTDIR/<test files> $TESTDIR/<link to $BASEDIR> Using an example program that I wrote, the following directory structure snippet works for me (where 'bin' is a directory to shared modules of production code): -rw-r--r-- 1 ken users 509 2004-11-30 13:35 label.ini lrwxrwxrwx 1 ken users 9 2004-12-29 01:54 bin -> ../../bin/ drwxr-xr-x 3 ken users 72 2004-12-10 16:01 data/ drwxr-xr-x 2 ken users 80 2004-12-10 16:46 disp/ drwxr-xr-x 2 ken users 48 2004-12-10 16:01 etc/ drwxr-xr-x 2 ken users 80 2004-12-10 16:27 prn/ drwxr-xr-x 2 ken users 208 2004-12-10 16:14 test/ drwxr-xr-x 2 ken users 1208 2004-12-10 17:15 label.py -- http://mail.python.org/mailman/listinfo/python-list