CHICAGO - Boeing Co completed what it called an uneventful flight on Saturday of a test 787 Dreamliner, its first since the airplanes were grounded more than three weeks ago after a series of battery-related problems.The test flight to gather detailed information on the airplane's lithium-ion batteries lasted two hours and 19 minutes, taking off from and returning to Boeing Field in Seattle, Boeing said."The crew reports that the flight was uneventful," Boeing said in a statement.