'package:test_api/test_api.dart' is deprecated and shouldn't be used.
package:test_api is not intended for general use. Please use package:test. Try replacing the use of the
deprecated member with the replacement.

The code was initially landed with the already-deprecated usage. I'm not sure why; my guess is that it relates to the way the code was moved from being in the tool itself, which has different dependency constraints.

Hopefully it will be a straightforward replacement with test, since this code is currently not clearly owned.