Having seen the thread of the 787 wings, I figured I might share this bit of information.
A while ago I was at a company called Smiths Aerospace in Wolverhampton.
(public listed company on the LSE, so all the information I am giving you can be found if you really dig for it, plus the guy who gave me the 'tour' was more than willing to show off the gadgets - very much appreciated and thanks to him)
Through work I was able to get a 'tour' of the testing area of Smiths, the company I work for supply some parts to Smiths.
Anyway, this place has thousands of square feet of warehouse space with very neat machinery which tests current and new aircraft parts wihch they make. Mainly primary/secondary controls and some landing gear parts. Basically the machines simulate real time effects of wind, load and pressure and repeat the standard movements ad infinitum. For instance, one machine moves the flaps back and forth to simulate several thousand hours of actual flight time, and they then analyze what happens to the mechanisms of the flap actuators etc...
Then I was shown the brand new test facility for the 787 wing. All the flaps, slats etc... were to be laid out in the shape of the wing in actual scaled size, and all this complex machinery would then test all the parts (moving them back and forth or up and down or side to side or in and out) together as if they were in flight. So all these machines (one for each mechanism) are automated to perform in such a way as to simulate flying conditions. And this cost several million pounds by the way.
I found this very impressive and was told other aircraft part suppliers do similar rigorous testing of parts. And it is extremely complex.
So whoever is complaining that there are delays for an ENTIRE aircraft, should step back and have a think. It takes years and millions of pounds of time and money to develop a small actuator which moves a flap. Combine this with thousands of other parts on a plane and you get an appreciation of how complex an aircraft is.