Similar setup for me as well. I usually develop on my Linux desktop but I also have a MacBook Air. I'd go nuts if I had to actually configure Postgres or an MQ server on it (or even manually in a VM). With Vagrant I have the exact same VM for both machines and its setup via a single "vagrant up".
An even more extreme example is a testing VM I setup with 5 copies of Postgres installed[1]. No mucking about locally and it's one command to spin it up. Way better than manually setting it up and so much easier to share too.
Your testing VM setup sounds like it might be really useful for the pgjdbc-ng project (a project to create a new JDBC driver for Postgres).
I was looking through the project issues on Github yesterday, prior to starting to play around with it and your comment reminded me that one of them was a note from the main developer asking for suggestions on automated testing. Perhaps you could send a pull request ?
An even more extreme example is a testing VM I setup with 5 copies of Postgres installed[1]. No mucking about locally and it's one command to spin it up. Way better than manually setting it up and so much easier to share too.
[1]: https://github.com/jackdb/pgjdbc-test-vm