Associated Press: After securing a new, tight-fitting cap on top of the leaking well in the Gulf of Mexico, BP prepared Tuesday to begin tests to see if it will hold and stop fresh oil from polluting the waters for the first time in nearly three months. The oil giant expects to know within 48 hours if the new cap, which was affixed Monday after almost three days of painstaking, around-the-clock work a mile below the Gulf’s surface, can stanch the flow. The solution is only temporary, but it offers the …