On Friday, 3 September 2021 at 23:39:44 UTC, Per Nordlöw wrote: > When is a phobos unittest supposed to be qualified with version > `(StdUnittest)`? Almost never. `version (StdUnittest)` should be used in Phobos wherever you would normally use a `version (unittest)` block. It is not for the tests themselves, but for test fixtures and support code.