replace empty with random in test to avoid nans
replace empty with random in test to avoid nans

jcrist/dask,mrocklin/dask,jakirkham/dask,dask/dask,chrisbarber/dask,mraspaud/dask,blaze/dask,dask/dask,blaze/dask,ContinuumIO/dask,jcrist/dask,ContinuumIO/dask,jakirkham/dask,mraspaud/dask,gameduell/dask,cpcloud/dask,mrocklin/dask