Build

sudo apt-get install build-essential libtool autotools-dev automake pkg-config libssl-dev libevent-dev bsdmainutils python3 libboost-system-dev libboost-filesystem-dev libboost-chrono-dev libboost-program-options-dev libboost-test-dev libboost-thread-dev

git clone https://github.com/bitcoin/bitcoin.git
cd bitcoin/

./autogen.sh
./configure --disable-wallet
make

Run testnet

./bitcoind -testnet

Also we could run cli on testnet

./src/bitcoin-cli -testnet getnetworkinfo
{
  "version": 169900,
  "subversion": "/Satoshi:0.16.99/",
  "protocolversion": 70015,
  "localservices": "000000000000040d",
  "localrelay": true,
  "timeoffset": 0,
  "networkactive": true,
  "connections": 8,
  "networks": [
    {
      "name": "ipv4",
      "limited": false,
      "reachable": true,
      "proxy": "",
      "proxy_randomize_credentials": false
    },
    {
      "name": "ipv6",
      "limited": false,
      "reachable": true,
      "proxy": "",
      "proxy_randomize_credentials": false
    },
    {
      "name": "onion",
      "limited": true,
      "reachable": false,
      "proxy": "",
      "proxy_randomize_credentials": false
    }
  ],
  "relayfee": 0.00001000,
  "incrementalfee": 0.00001000,
  "localaddresses": [
  ],
  "warnings": "This is a pre-release test build - use at your own risk - do not use for mining or merchant applications"
}