tree 0940bbc4109138fdc9c3b0825ad7baca35112cfe
parent 1cd11a05a2288c352a852991a53e9cf3f7f5ee24
author Vadim Yanitskiy <axilirator@gmail.com> 1547251498 +0700
committer Vadim Yanitskiy <axilirator@gmail.com> 1547252585 +0700

BTS_Tests.ttcn: fix: use TRXC interface of the BTS side, not BB

It was observed that 'BTS_Tests.TC_rach_max_ta' started to fail
with the following reason: "BTS_Tests.ttcn:1091 : RACH passed
but was expected to be dropped: -2560".

My initial assumption was that the test case basically sends
FAKE_TOA command on a wrong TRXC interface, and it was
confirmed using trx_sniff.py:

  # TRXD of the BB side
  $ ./trx_sniff.py -p 6700
  [DEBUG] trx_sniff.py:110 L1 -> TRX burst: fn=616 tn=0 pwr=0
  [DEBUG] trx_sniff.py:110 TRX -> L1 burst: fn=597 tn=0 rssi=-60 toa256=-2560
  [DEBUG] trx_sniff.py:110 TRX -> L1 burst: fn=598 tn=0 rssi=-60 toa256=-2560
  ...

  # TRXD of the BTS side (Uplink bursts only)
  $ ./trx_sniff.py -p 5700 --direction L1
  [DEBUG] trx_sniff.py:110 TRX -> L1 burst: fn=719 tn=0 rssi=-60 toa256=0

and additionally be enriching logging messages of fake_trx.py:

  [DEBUG] fake_trx.py:186 (trx@0.0.0.0:6700) Recv FAKE_TOA cmd

Sending FAKE_* commands on TRXC interface of the BB side affects
the bursts being forwarded to this side, so we should use the
TRXC interface of the BTS side to simulate Uplink delay.

The reason why the test case has been passing some time ago is
that there was a bug in fake_trx.py, that has been fixed recently.

This patch makes 'BTS_Tests.TC_rach_max_ta' green again ;)

Change-Id: I7736abd85407c186856be9f1a22613a1fa6e0c32