Hi Antti,

> What we are trying to do is a full stack system testing where the
> individual components that are being tested don't have any modifications
> or adaptations when they are run under test suite.

Okay that sort of makes sense

> 
> The number of modems returned by org.ofono.Manager.GetModems() must
> represent the total number of modems available to the system and thus we
> need to have exactly two modems when testing dual-sim features etc.
> 

Sounds like your system is a bit inflexible, but okay.

> The need to change the number of modems during testing comes from the
> fact that our test suite has the single and multimodem tests together
> and runs them one after another and we need to be able to set up the
> environment appropriately in between individual test cases.
> 

Why don't you simply write a plugin that handles all of this?  E.g.
canonical_tester that creates two modem instances.  If you must insist
on having exactly 1 or 2 modems, then just add a DBus interface to
switch between modes.

Adding a control mechanism for controlling the number of phonesim
instances seems like total overkill.

Regards,
-Denis