New York Times: After three days of encouraging test results, BP said Sunday that it planned to leave its well in the Gulf of Mexico closed until it could be permanently plugged, perhaps in several weeks. There has been no oil leaking into the gulf since Thursday, when valves on a new cap atop the well were closed for the test, an effort that was initially seen as a stopgap measure. But if conditions allow BP to continue to keep the cap closed, the gusher, which spewed tens of millions of gallons of …