NIGERIAN state-owned oil firm NNPC Ltd will complete test runs at the Port Harcourt refinery in the south this month, in a major step towards resuming operations five years after the plant was shut, the company said. "Testing will conclude shortly, ensuring the refinery's efficient operation. That phase will be completed this month," NNPC spokesperson Femi Soneye said. The refinery, which is undergoing an upgrade, will begin by processing 60,000 barrels per day, and NNPC expects to operate at the full capacity of 210,000 barrels per day later this year. Port Harcourt is among Nigerian state-owned refineries that have been…