For those that use a cabal based workflow on Windows or are interested in doing Windows testing for their packages using AppVeyor I've written up some instructions on how to do this using Chocolatey https://hub.zhox.com/posts/chocolatey-introduction/.
The standard packages are pulled directly from Haskell.org
As a trial I'm also making my own Windows Nightlies for GHC and Cabal available via my NuGet package stream.