Tests failing on Beta & Nightly

[ChrisMacNaughton]

It looks like the workspace test --all command has expanded to include doc tests so this line is causing beta to fail tests, it should either be correct code (with a comment of the variable nature), be replaced with Vec::new(), or be explicitly excluded from being built

[cholcombe973]

Thanks for spotting this. I've put up a PR which looks to have fixed it.