test-perms.sh

#!/bin/bash

# this script is not editable and should not be run as root

mkdir /tmp/permstest/subdir

test-perms.yml

---                                                                                
- hosts: all
  tasks:
    - name: create permstest group
      sudo: yes
      group: name=permstest state=present

    - name: create dir owner=root group=permstest mode=0775
      sudo: yes
      file: dest=/tmp/permstest owner=root group=permstest
            state=directory mode=0775

    - name: add ansible user to permstest group
      sudo: yes
      user: name={{ ansible_user_id }} groups=permstest
            append=yes

    - name: try to create subdir as ansible user
      script: test-perms.sh

Vagrantfile

Vagrant.configure(2) do |config|
  config.vm.box = "precise64"
  config.vm.provision "ansible" do |ansible|                               
    ansible.playbook = "test-perms.yml"                          
  end 
end