The extended testsuite only works with uid=0. It contains of several
subdirectories named "test/TEST-??-*", which are run one by one.

To run the extended testsuite do the following:

$ make all
$ cd test
$ sudo make clean check
...
make[1]: Entering directory `/mnt/data/harald/git/systemd/test/TEST-01-BASIC'
Making all in .
Making all in po
Making all in docs/libudev
Making all in docs/gudev
TEST: Basic systemd setup [OK]
make[1]: Leaving directory `/mnt/data/harald/git/systemd/test/TEST-01-BASIC'
...

If one of the tests fails, then $subdir/test.log contains the log file of
the test.

To debug a special testcase of the testsuite do:

$ make all
$ cd test/TEST-01-BASIC
$ sudo make clean setup run

If you want to log in the testsuite virtual machine, you can specify
additional kernel command line parameter with $DEBUGFAIL.

$ sudo make DEBUGFAIL="systemd.unit=multi-user.target" clean setup run

you can even skip the "clean" and "setup" if you want to run the machine again.

$ sudo make DEBUGFAIL="systemd.unit=multi-user.target" run