[Meta issue, opening separate issues for test cases]

The default install always installs the testsuite together with all the python batteries. So make sure that you can run the testsuite can run from the installed location too.

 - some tests require the sources to run (using the srcdir macro,
   or files not installed, e.g. xxmodule.c).

 - some tests assume write permissions.

 - some tests assume not being run as root.