Add comment about running integration tests from the Vagrant build VM

test/README.md

@@ -18,6 +18,9 @@ To meet the aforementioned ssh requirement you may want to
 
 ## Running tests
 
+If you are [building weave using Vagrant](http://docs.weave.works/weave/latest_release/building.html),
+it is recommended to run the tests from the build VM and not the host.
+
     ./setup.sh
 
 uploads the weave images from where the Makefile puts them