Cosmic voids can supply powerful insights into the nature of dark energy, provided that we have accurate models of their statistical properties. In this talk I will present a new method to identify and predict void density profiles, and show how we can reduce systematic errors when probing the growth rate around voids. This will be crucial for testing non-standard dark energy models with upcoming large survey campaigns. Finally, I will also present a self-consistent measurement of the growth rate around galaxies and around voids, in the 6-degree Field Galaxy Survey, as a test of the standard model of gravity.