portlock provides a mechanism for containers to acquire and release ports they plan to expose, and a wait mechanism This allows tests dependent on running containers to always parallelize without having to worry about port collision with any other test Note that this does NOT protect against trying to use a port that is already used by an unrelated third-party service or container Also note that *generally* finding a free port is not easy: - to just "listen" and see if it works won't work for containerized services that are DNAT-ed (plus, that would be racy) - inspecting iptables instead (or in addition to) may work for containers, but this depends on how networking has been set (and yes, it is also racy) Our approach here is optimistic: tests are responsible for calling Acquire and Release.

Identifier can be used as a name of container, image, volume, network, etc.

ImageRepo returns the image repo that can be used to, e.g, validate output from `nerdctl images`.

Load is used only for unit testing.

NewDelayOnceReader returns a wrapper around io.Reader that delays the first Read() by one second.

RegisterBuildCacheCleanup adds a 'builder prune --all --force' cleanup function to run on test teardown.

RequireExecutable skips tests when executable `name` is not present in PATH.

SetupDockerContainerBuilder creates a Docker builder using the docker-container driver and adds cleanup steps to test cleanup.

WithStdin sets the standard input of Cmd to the specified reader.

eStargz.

SOCI.

Large enough for testing soci index creation.

This error string is expected when attempting to connect to a TCP socket for a service which actively refuses the connection.

Foreign layer digest.

Source: https://gist.github.com/cpuguy83/fcf3041e5d8fb1bb5c340915aabeebe0.