This project is the implementation of the ERC20 Cent Token.
Where possible we have inherited from the audited OpenZepplin contracts but we have also added additional features including an implementation of ERC2612.
ERC2612 enables the use of off-chain signatures to increase allowances using permit. Calls to permit don't need to be done by the holder and so this enables support for "gas-less" tokens, or the replacement of approve transactions by methods that call permit and transferFrom atomically.
This contract was written by Switch1983.
The implementation of ERC2612 was heavily influenced by the work of Georgios Konstantopoulos and Alberto Cuesta Cañada.
CentToken is an ERC20 contract. To test, make sure that you have Ganache-cli and Truffle installed alone with NodeJS.
Switch to a suitable version of Node
nvm install 10.22.1
Install dependencies
npm install
Run tests
truffle test
The utils/signatures.ts file contains useful functions to compute the DOMAIN_SEPARATOR, digest and signature from typescript.
A good way to become familiar with the Cent token and to carry our realtime testing is from the Truffle console.
Start the Ganache network
ganache-cli -h 0.0.0.0 --deterministic --gasLimit 10000000
Test the Ganache client is running
curl http://127.0.0.1:8545 \
-X POST \
-H "Content-Type: application/json" \
-d '{"jsonrpc": "2.0", "method": "web3_clientVersion"}'
You should see output similar to the following.
curl -X POST --data '{"jsonrpc":"2.0","method":"eth_getCode","params":["0xCfEB869F69431e42cdB54A4F4f105C19C080A601", "latest"],"id":1}' localhost:8545
With Ganache running we now deploy our contracts.
truffle migrate
Now start the Truffle console for interactive testing.
truffle console
The following are examples of commands you can issue to interact with the Cent contract. Be aware that the account used for minting or snapshotting must match what was set in the migration config file.
// To get a reference to CentToken
let instance = await CentToken.deployed()
instance
// Mint coins
let accounts = await web3.eth.getAccounts()
instance.mint(accounts[2], 100, {from: accounts[0]})
// Check balance
let balance = await instance.balanceOf(accounts[2])
balance.toNumber()
// burn tokens
// Only the account holding tokens can burn their own tokens
instance.burn(10, {from: accounts[2]})
balance = await instance.balanceOf(accounts[2])
balance.toNumber()
// Allowance testing
// Account 2 gives account 3 an allowance of 10 to spend meaning account 3 can spend up to 10 of account 2 balance
instance.increaseAllowance(accounts[3], 10, {from: accounts[2]})
// Account 3 now sends 5 from account 2's account to account 4
instance.transferFrom(accounts[2], accounts[4], 5, {from: accounts[3]})
// Burn one of that accounts allowed tokens as well
instance.burnFrom(accounts[2], 1, {from: accounts[3]})
balance = await instance.balanceOf(accounts[2])
balance.toNumber()
// Grant MINTER_ROLE test
// should fail
instance.grantRole("0x9f2df0fed2c77648de5860a4cc508cd0818c85b8b8a1ab4ceeef8d981c8956a6", accounts[5], {from: accounts[5]})
// should work
instance.grantRole("0x9f2df0fed2c77648de5860a4cc508cd0818c85b8b8a1ab4ceeef8d981c8956a6", accounts[5], {from: accounts[0]})
// Revoke a role
instance.revokeRole("0x9f2df0fed2c77648de5860a4cc508cd0818c85b8b8a1ab4ceeef8d981c8956a6", accounts[5], {from: accounts[0]})
// Give role again and then renounce that role
instance.grantRole("0x5fdbd35e8da83ee755d5e62a539e5ed7f47126abede0b8b10f9ea43dc6eed07f", accounts[5], {from: accounts[0]})
instance.renounceRole("0x5fdbd35e8da83ee755d5e62a539e5ed7f47126abede0b8b10f9ea43dc6eed07f", accounts[5], {from: accounts[5]})
// Transfer some tokens
instance.transfer(accounts[4], 5, {from: accounts[2]})
// Snapshot tests
instance.totalSupply({from: accounts[1]})
instance.snapshot({from: accounts[1]})
instance.totalSupplyAt(1, {from: accounts[1]})
instance.mint(accounts[2], 250, {from: accounts[0]})
instance.totalSupply({from: accounts[1]})
instance.totalSupplyAt(1, {from: accounts[1]})
instance.balanceOfAt(accounts[2], 1, {from: accounts[1]})
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