BSC_Tests: fix TC_lost_sdcch_during_assignment (SCCPlite)

When running ttcn3-bsc-test against osmo-bsc in SCCPlite mode,
TC_lost_sdcch_during_assignment fails with the following output:

  Local verdict of MTC: fail reason: "Timeout of T_guard"
  Final verdict of PTC: fail reason: "Unexpected DLCX received"

One key problem is that in f_TC_lost_sdcch_during_assignment() we
expect to receive a DLCX message on port MGCP, but somehow it gets
caught by the as_Media_mgw earlier than we attempt to receive it.

* Fix this race condition by activating the as_Media_mgw with
  fail_on_dlcx := false, so that it does not catch DLCX messages.

Another problem is that for SCCPlite we're running the MGCP_Emulation
component with multi_conn_mode=true, so that all MGCP messages are
arriving at port MGCP_MULTI (not MGCP) wrapped into MGCP_RecvFrom.

* Expect the DLCX message on either of the two ports depending
  on the value of g_pars.aoip (AoIP or SCCPlite mode).

This change makes BSC_Tests.TC_lost_sdcch_during_assignment pass.

Change-Id: If4807d3d7d196682f7f22732ad47bcbb72858ed3
1 file changed