Use mitchellh/go-testing-interface instead of "testing"
Use mitchellh/go-testing-interface instead of "testing"

This prevents the global test flags from polluting the flags global
namespace and prevents a runtime dependency on "testing" if it can be
prevented.

mitchellh/go-testing-interface exports an interface that exposes the
testing.T functions and has no other dependencies.

hashicorp/go-getter,missedone/go-getter