verify that re-using ARFCN+BSIC pairs within a BSS works
Any ARFCN+BSIC pair may be used any number of times in a BSS.
If a given cell reports good RXLEV for a specific ARFCN+BSIC, the eligible target cells shall be only those listed as explicit neighbors for the source cell.
However, in handover_start(), it looks like any cell with a matching ARFCN+BSIC would be picked by bts_by_neighbor_ident().
Verify in a test that explicit neighbors work as expected, even if their ARFCN+BSIC is used multiple times within the BSS,
i.e. that only the specific cell which is listed as explicit neighbor is picked as target, not another one with the same ARFCN+BSIC that is not listed as explicit neighbor for the handover source cell.
The OsmoBSC manual claims that this works, but the code to me looks like it wouldn't.