rootless docker does not pass tests

[dominictarr]

I've been trying this with rootless docker. (so you don't have to run sudo docker on every command...)

it has weirdly different behavior. It fails the tests with a network error - ECONREFUSED. Weirdly, it gets part way through and then fails.

Also, rootless docker is much slower. With root, the tests pass in 15 seconds, without root, they fail after 45 seconds, on the 3rd test of 5!