hugofs: Add missing not nil checks to tests
hugofs: Add missing not nil checks to tests

fedelibre/hugo,ffrizzo/hugo,vbatoufflet/hugo,anthonyfok/hugo,melo/hugo,bogem/hugo,digitalcraftsman/hugo,vbatoufflet/hugo,gohugoio/hugo,MarkDBlackwell/hugo,Zenithar/hugo,MarkDBlackwell/hugo,mdhender/hugo,tubo028/hugo,mdhender/hugo,gohugoio/hugo,soundrussian/hugo,ffrizzo/hugo,tubo028/hugo,soundrussian/hugo,mitchchn/hugo,gohugoio/hugo,mitchchn/hugo,abourget/hugo,digitalcraftsman/hugo,tischda/hugo,fedelibre/hugo,abourget/hugo,anthonyfok/hugo,anthonyfok/hugo,melo/hugo,mayah/hugo,jygastaud/hugo,mdhender/hugo,tischda/hugo,fedelibre/hugo,fedelibre/hugo,jygastaud/hugo,mayah/hugo,mdhender/hugo,Zenithar/hugo,bogem/hugo