Ampleforth Property Tests •

A project to collect and test properties of Ampleforth's AMPL token.

Overview

This repo offers an executable, property-based test suite for Ampleforth's AMPL token.

For more info, see the accompanying post Property-based Testing Ampleforth.

Properties

Note

Any contributions to add more properties to the project are highly welcome!

The project currently tests the following properties:

Rebase Properties:

• The gon-AMPL conversion rate is the (fixed) scaled total supply divided by the (elastic) total supply
• The rebase operation is non-dilutive, i.e. does not change the wallet wealth distribution

Total Supply Properties:

• The total supply never exceeds the defined max supply
• The total supply is never zero
• The sum of all balances never exceeds the total supply
  • Note that rebase tokens can not guarantee that the sum of all balances equals the total supply
  • For more info, see here

Transfer Properties:

• A transfer of x AMPLs from user A to user B results in A's external balance being decreased by precisely x AMPLs and B's external balance being increased by precisely x AMPLs
• A transfer of zero AMPL is always possible
• Calling the tranferAllFrom function reverts when the balance of the owner is non-zero and the allowance of the spender is zero

Usage

The project uses the Foundry toolchain. You can find installation instructions here.

Clone repo:

$ git clone https://github.com/pmerkleplant/ampleforth-property-tests

Install dependencies:

$ cd ampleforth-property-tests
$ forge install

Run test suite:

$ forge test

Run test suite with full stack trace:

$ forge test -vvvv

Trophies

• Via the transferAllFrom function its possible to steal a non-zero amount of gons iff the derived AMPL amount rounds down to zero.

License

GNU General Public License v3.0 (c) 2022 merkleplant