Currently you can't use "devpi test" with wheel files because they don't contain the tests unless you put all tests inside the software archive. To get the tests we could require that there is an "sdist" archive file containing the "tox.ini" file and the tests. Thus "devpi test X" would potentially download two files, a platform specific one and the sdist to configure and perform testing.
Apart from running the tests against the sdist we probably also want to run the tests against the installed sdist. Not sure i grasp all implications yet (also UI wise) but does anyone of you have preliminary thoughts on the issue?