ricmd test function, check docker

The ri_test_... functions are meant for package testing and setting up a demo environment. These functions are not intended for package users. Checks if a docker environment exists

Usage

ri_test_check_docker(verbose = FALSE)

Arguments

verbose

Give verbose output

Check if Docker is installed and can be accessed without sudo rights.

Function copied from rirods package, https://github.com/irods/irods_client_library_rirods, Martin Schobben