The simplest option is to use the testchain.json included in this folder.
Alternatively, you can create one by copying the mainnet blockchain config src/main/resources/blockchain.json
Insert "isTestChain": true, after the opening {
Modify testnet genesis block, feature triggers etc

Testnet genesis block

Set timestamp to a nearby future value, e.g. 15 mins from 'now' This is to give yourself enough time to set up other testnet nodes
Retain the initial ISSUE_ASSET transactions!
Add ACCOUNT_FLAGS transactions with "andMask": -1, "orMask": 1, "xorMask": 0 to create founders
Add at least one REWARD_SHARE transaction otherwise no-one can mint initial blocks! You will need to calculate rewardSharePublicKey (and private key), or make a new account on mainnet and use self-share key values
Add ACCOUNT_LEVEL transactions to set initial level of accounts as needed
Add GENESIS transactions to add QORT/LEGACY_QORA funds to accounts as needed

Testnet `settings.json`

Create a new settings-test.json
Make sure to add "isTestNet": true,
Make sure to reference testnet blockchain config file: "blockchainConfig": "testchain.json",
It is a good idea to use a separate database: "repositoryPath": "db-testnet",
You might also need to add "bitcoinNet": "TEST3", and "litecoinNet": "TEST3",
Also make sure to use a custom listenPort (not 62391 or 12391) to ensure that transactions remain isolated to your testnet.

Other nodes

Copy testchain.json and settings-test.json to other nodes
Alternatively, you can run multiple nodes on the same machine by:
- Copying settings-test.json to settings-test-1.json
- Configure different repositoryPath
- Configure use of different ports:
  - "apiPort": 22391,
  - "listenPort": 22392,

Starting-up

Start up at least as many nodes as minBlockchainPeers (or adjust this value instead)
Probably best to perform API call DELETE /peers/known
Add other nodes via API call POST /peers <peer-hostname-or-IP>
Add minting private key to nodes via API call POST /admin/mintingaccounts <minting-private-key> The keys must have corresponding REWARD_SHARE transactions in testnet genesis block
You must have at least 2 separate minting keys and two separate nodes. Assign one minting key to each node.
Alternatively, comment out the if (mintedLastBlock) { } conditional in BlockMinter.java to allow for a single node and key.
Wait for genesis block timestamp to pass
A node should mint block 2 approximately 60 seconds after genesis block timestamp
Other testnet nodes will sync *as long as there is at least minBlockchainPeers peers with an "up-to-date" chain`
You can also use API call POST /admin/forcesync <connected-peer-IP-and-port> on stuck nodes

Single-node testnet

A single-node testnet is possible with an additional settings, or to more easily start a new testnet. Just add this setting:

"singleNodeTestnet": true

This will automatically allow multiple consecutive blocks to be minted, as well as setting minBlockchainPeers to 0. Remember to put these values back after introducing other nodes.

Fixed network

To restrict a testnet to a set of private nodes, you can use the "fixed network" feature. This ensures that the testnet nodes only communicate with each other and not other known peers. To do this, add the following setting to each testnet node, substituting the IP addresses:

"fixedNetwork": [
  "192.168.0.101:62392",
  "192.168.0.102:62392",
  "192.168.0.103:62392"
]

Dealing with stuck chain

Maybe your nodes have been offline and no-one has minted a recent testnet block. Your options are:

Start a new testnet from scratch
Fire up your testnet node(s)
Force one of your nodes to mint by:
- Set a debugger breakpoint on Settings.getMinBlockchainPeers()
- When breakpoint is hit, change this.minBlockchainPeers to zero, then continue
Once one of your nodes has minted blocks up to 'now', you can use "forcesync" on the other nodes

Tools

qort tool, but use -t option for default testnet API port (62391)
qort tool, but first set shell variable: export BASE_URL=some-node-hostname-or-ip:port
qort tool, but prepend with one-time shell variable: BASE_URL=some-node-hostname-or-ip:port qort ......
peer-heights, but use -t option, or BASE_URL shell variable as above

Example settings-test.json

{
  "isTestNet": true,
  "bitcoinNet": "TEST3",
  "litecoinNet": "TEST3",
  "dogecoinNet": "TEST3",
  "digibyteNet": "TEST3",
  "ravencoinNet": "TEST3",
  "repositoryPath": "db-testnet",
  "blockchainConfig": "testchain.json",
  "minBlockchainPeers": 1,
  "apiDocumentationEnabled": true,
  "apiRestricted": false,
  "bootstrap": false,
  "maxPeerConnectionTime": 999999999,
  "localAuthBypassEnabled": true,
  "singleNodeTestnet": true,
  "recoveryModeTimeout": 0
}

Quick start

Here are some steps to quickly get a single node testnet up and running with a generic minting account:

Start with template settings-test.json, and testchain.json which can be found in this folder. Copy/move them to the same directory as the jar.
Set a custom listenPort in settings-test.json (not 62391 or 12391) to ensure that transactions remain isolated to your testnet.
Make sure feature triggers and other timestamp/height activations are correctly set. Generally these would be 0 so that they are enabled from the start.
Set a recent genesis timestamp in testchain.json, and add this reward share entry: { "type": "REWARD_SHARE", "minterPublicKey": "DwcUnhxjamqppgfXCLgbYRx8H9XFPUc2qYRy3CEvQWEw", "recipient": "QbTDMss7NtRxxQaSqBZtSLSNdSYgvGaqFf", "rewardSharePublicKey": "CRvQXxFfUMfr4q3o1PcUZPA4aPCiubBsXkk47GzRo754", "sharePercent": 0 },
Start the node, passing in settings-test.json, e.g: java -jar qortal.jar settings-test.json
Once started, add the corresponding minting key to the node: curl -X POST "http://localhost:62391/admin/mintingaccounts" -d "F48mYJycFgRdqtc58kiovwbcJgVukjzRE4qRRtRsK9ix"
Alternatively you can use your own minting account instead of the generic one above.
After a short while, blocks should be minted from the genesis timestamp until the current time.

README.md

How to build a testnet

Create testnet blockchain config