make the testsuite a little less brittle:

make the testsuite a little less brittle:
- 'function fn_name\n{' breaks on older FreeBSD default shells, so use the more
  widely supported 'fn_name () {'. This needs more fixing..
- test for integers ought to use the proper operators
- test for strings ought to use quoting of the strings to be fair to strange
  implementations of test(1)
- make sure not to ignore return-codes != 0 from commands; Some shells exit
  immediately on this (much like explicitely requesting set -e in e.g. bash)

TODO:
*) Some older shells do not allow a space after the test-condition in an "if"
statement. This doesn't work:
if [ $status -ne 0 ] ; then
as opposed to this:
if [ $status -ne 0 ]; then
or this
if [ $status -ne 0 ]
then

*) strict spacing between commands. In some shells you have to say:
foo ; bar ; baz
The affected shells barf on stuff like ommitting the space, so this doesn't
work:
foo; bar   ;baz

*) $() vs. ``
The former isn't really portable as opposed to the latter.

*) fix frong assumption that the testsuite is run from the source-dir.
This is a complete misconception and renders the testsuite completely useless.

That said, i note that IMO a test-harness ought to do it's best to work in
a wide variety of environments, everything else defeats it's purpose.