env GO111MODULE=on

go mod graph
stdout '^m rsc.io/quote@v1.5.2$'
stdout '^rsc.io/quote@v1.5.2 rsc.io/sampler@v1.3.0$'
! stdout '^m rsc.io/sampler@v1.3.0$'
! stderr 'get '$GOPROXY

rm $GOPATH/pkg/mod/cache/download/rsc.io/quote
go mod graph -x
stderr 'get '$GOPROXY

-- go.mod --
module m
require rsc.io/quote v1.5.2