# With no .gomodproxy supporting files, we use the GOPROXY from
# the environment.
env GOPROXY=0.1.2.3
unquote file.txt
testscript -v file.txt

-- file.txt --
>go env
>[!windows] stdout '^GOPROXY="0.1.2.3"$'
>[windows] stdout '^set GOPROXY=0.1.2.3$'