Run tests with other unreleased core packages?

[davisagli]

Currently tests run using the dev constraints (e.g. https://dist.plone.org/release/6.3-dev/constraints.txt) which means that if multiple packages are being changed, the changes aren't used in tests until the packages are released and the constraints are updated.

I wonder if we could manage to make the meta tox configuration install the same combination of released and in-development packages that are used in buildout.coredev. Maybe it is possible to make it run mxdev with a configuration that extends https://github.com/plone/buildout.coredev/blob/6.3/mx.ini?

[mauritsvanrees]

FWIW, I have made releases, and have updated https://dist.plone.org/release/6.3-dev/