add tests for delete
add tests for delete

nuest/o2r-muncher,o2r-project/o2r-muncher,nuest/o2r-muncher,nuest/o2r-muncher,o2r-project/o2r-muncher,o2r-project/o2r-muncher,o2r-project/o2r-muncher,nuest/o2r-muncher,o2r-project/o2r-muncher,nuest/o2r-muncher