=== ls /data/ ===
hello world
revenue,100\nexpense,80
name=hello.txt size=12
"alice"
`-- user.json
/data/hello.txt
HELLO WORLD
goodbye world
dlrow olleh
6f5902ac237024bdd0c176cb93063dc4
aGVsbG8gd29ybGQK
= 41 bytes (2 reads)
copy() sees original's writes: hello world
wiped test keys from Redis
