extend unit test to cover previous bug
extend unit test to cover previous bug

mjbshaw/Eigen,madlib/eigen_backup,mjbshaw/Eigen,rotorliu/eigen,madlib/eigen_backup,madlib/eigen_backup,rotorliu/eigen,rotorliu/eigen,rotorliu/eigen,mjbshaw/Eigen,madlib/eigen_backup,mjbshaw/Eigen