# How to build a testnet
## Create testnet blockchain config
- You can begin by copying the mainnet blockchain config `src/main/resources/blockchain.json`
- Insert `"isTestChain": true,` after the opening `{`
- Modify testnet genesis block
### 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",`
## 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 code modifications, for basic testing, or to more easily start a new testnet.
To do so, follow these steps:
- Comment out the `if (mintedLastBlock) { }` conditional in BlockMinter.java
- Comment out the `minBlockchainPeers` validation in Settings.validate()
- Set `minBlockchainPeers` to 0 in settings.json
- Set `Synchronizer.RECOVERY_MODE_TIMEOUT` to `0`
- All other steps should remain the same. Only a single reward share key is needed.
- 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
