BP begins critical test

Valves have been closed on a the new cap and now it's just a question of whether the pressure can hold. From the NYT:

The test is expected to take as little as 6 hours to 48 hours or more. A short test would mean bad news: the well could not hold pressure from the leaking oil, like a leaky soda bottle. "We sat long and hard about this test," Thad W. Allen, the retired Coast Guard admiral who is the national incident commander, said in a news conference. "In the interest of the American people, and the safety of the environment, it was advisable to take a 24-hour break to make sure were getting it absolutely right."