D-Bus testing: improved running of command line tool

Refactored the code into a new utility base class for use in other
tests.

Replace pipes with temporary files, using the same base name as the
traditional .syncevo.log and .dbus.log. They are numbered (because the
command line might be run multiple times per test) and use .out, .err,
or .outerr as suffix depending on what kind of output they
contain. The advantage is that the output gets recorded permanently.

Use that when waiting for command completion times out: in that case,
the content of the output file(s) gets added to the exception.

The subprocess handle returned by startCmdline() is extended with
information about output redirection that is then used by
finishCmdline(). This makes one parameter of finishCmdline()
redundant.

0 files changed, 0 insertions, 0 deletions