The alpha Casper the Friendly Finality Gadget (FFG) testnet allows both PoW and PoS. These are instructions on how to mine testnet ETH using Ubuntu 16.04 LTS

mining_casper_ffg_testnet_eth_with_ubuntu_16_04.txt

sudo apt-get update 
sudo apt-get upgrade 
sudo apt-get install curl
sudo apt-get install make
curl -fsSL get.docker.com -o get-docker.sh 
sudo sh get-docker.sh 
sudo usermod -aG docker $USER 
sudo shutdown -r now
sudo apt-get install git
git clone https://github.com/karlfloersch/docker-pyeth-dev.git 
cd docker-pyeth-dev
make new-account
make run-node mine_percent=90 bootstrap_node=enode://d3260a710a752b926bb3328ebe29bfb568e4fb3b4c7ff59450738661113fb21f5efbdf42904c706a9f152275890840345a5bc990745919eeb2dfc2c481d778ee@54.167.247.63:30303