How should multiple (related) projects be arranged (structured) and configured so that they can share code, have a related package structure and enable proper unittesting, and ensuring no namespace collisions

[alisonken1]

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