The spar problems don't seem trivial having been discovered so late.
They have started taxi tests, needed to test braking systems, prove it can go at least 100 kts on the ground, and so forth.
>>A Closer Look: 787 Taxi Testing By Jon Ostrower July 8, 2009 3:07 PM ...The tests looked at the low speed handling characteristics of the aircraft by exploring of the anti-skid system, steering, nose gear shimmy and ground loads validation, says a program source...<< http://www.flightglobal.com/blogs/flightblogger/2009/07/more-on-787-taxi-testing.html