I think the best thing you can do for the fledgling test sides is actually play against them ! None of this crap like oz not playing in Bangladesh since 2011 or 2009 or whenever it was . We haven't had them in Australia since mid year tours where they were 'afforded the luxury' of playing in darwin and cairns . Same as Zimbabwe, who i know have had their troubles recently , but I'm sure heath streak was still around the last time they were in Australia. Not goood enough ! Play them home and away more often . If Zimbabwe only ever play bangladesh and the west indies and affiliates then they'll never improve beyond a certain point .
Also , we need to get pakistan back playing true home tests asap. That will not only help their cricket and finances , it will help everyone else too . Afghanistan could play some 'home' games in Pakistan too (if pakistan was able to host international cricket) instead of in india .
Aganistan should be played by any touring party heading to play pakistan , sri lanka , bangladesh , or india . Similarly , Ireland should be get a test or two before any nation tours england (or even the windies) ... this is the least we can all do .