bug fix in unit test
bug fix in unit test

amandalund/openmc,smharper/openmc,liangjg/openmc,walshjon/openmc,smharper/openmc,liangjg/openmc,smharper/openmc,paulromano/openmc,smharper/openmc,amandalund/openmc,mit-crpg/openmc,shikhar413/openmc,shikhar413/openmc,mit-crpg/openmc,amandalund/openmc,walshjon/openmc,mit-crpg/openmc,shikhar413/openmc,shikhar413/openmc,paulromano/openmc,paulromano/openmc,walshjon/openmc,paulromano/openmc,liangjg/openmc,walshjon/openmc,liangjg/openmc,mit-crpg/openmc,amandalund/openmc