BBC: Oil firm BP is awaiting test results from the blown-out well in the Gulf of Mexico, a day after staunching the flow of oil for the first time since April. The firm is checking how much pressure the well can withstand while the valves on its new capping device are closed. US President Barack Obama hailed the move as a “positive sign”, and BP’s shares rallied in early trading in London after sharp rises in New York. Oil has been flowing from the well since a rig exploded …