OUSD Fuzzing Campaign

Invariants

• Transfer
  • The receiving account's balance after a transfer must not increase by less than the amount transferred
  • The receiving account's balance after a transfer must not increase by more than the amount transferred
  • The sending account's balance after a transfer must not decrease by less than the amount transferred
  • The sending account's balance after a transfer must not decrease by more than the amount transferred
  • The receiving account's balance after a transfer must not increase by less than the amount transferred (minus rounding error)
  • The sending account's balance after a transfer must not decrease by less than the amount transferred (minus rounding error)
  • An account should always be able to successfully transfer an amount within its balance.
  • An account should never be able to successfully transfer an amount greater than their balance.
  • A transfer to the same account should not change that account's balance
  • Transfers to the zero account revert
• Supply
  • After a changeSupply, the total supply should exactly match the target total supply. (This is needed to ensure successive rebases are correct).
  • The total supply must not be less than the sum of account balances. (The difference will go into future rebases)
  • Non-rebasing supply should not be larger than total supply
  • Global rebasingCreditsPerToken should never increase
  • The rebasing credits per token ratio must greater than zero
  • The sum of all non-rebasing balances should not be larger than non-rebasing supply
  • An accounts credits / credits per token should not be larger it's balance
• Accounting
  • After opting in, balance should not increase. (Ok to lose rounding funds doing this)
  • Account balance should remain the same after opting in minus rounding error
  • After opting out, balance should remain the same
  • After opting in, total supply should remain the same
  • After opting out, total supply should remain the same
  • Account balance should remain the same when a smart contract auto converts
  • The balanceOf function should never revert
• Mint & Burn
  • Minting 0 tokens should not affect account balance
  • Burning 0 tokens should not affect account balance
  • Minting tokens must increase the account balance by at least amount
  • Burning tokens must decrease the account balance by at least amount
  • Minting tokens should not increase the account balance by less than rounding error above amount
  • A burn of an account balance must result in a zero balance
  • You should always be able to burn an account's balance
• Approvals
  • Performing transferFrom with an amount inside the allowance should not revert
  • Performing transferFrom with an amount outside the allowance should revert
  • Approving an amount should update the allowance and overwrite any previous allowance
  • Increasing the allowance should raise it by the amount provided
  • Decreasing the allowance should lower it by the amount provided