Testing disputable contracts

Guide and API description of different mock contracts.

The celeste-helpers package provides a number of mocks which simulate the DisputeManger, AragonCourt and Arbitrator Manifest API's and their functionality on a basic level. This should help when creating tests for Disputable contracts as you can avoid all the overhead necessary to fork xDai or even deploy a full Celeste instance in your test environment.

TestERC20

As the name implies is an ERC20 token that is easy to instantiate for tests. TestERC20 supports all standard ERC20 methods and events along with additional methods defined in@openzeppelin/contracts/token/ERC20/ERC20.sol.

This contract takes no constructor arguments. The deployer address will automatically be assigned as the token owner. Ownership can queried, transferred and revoked based on Openzeppelin's Ownable API.

TestERC20.mint(address, uint256) -> ()

Parameters:

• address _recipient: Recipient of newly minted test tokens

• uint256 _amount: Amount of test tokens to be minted

Emitted events:

In accordance to the recommendation in the ERC20 spec a ERC20.Transfer event is transferred with the from address being the zero address and the to address being the _recipient

General function

Method issues new tokens to recipient. Reverts if caller is not the owner. This is to avoid accidental mints within your tests.

DisputeManager and AragonCourt mocks

The mock for these contracts is a single contract taking up the functionality and the API of both. The mock only simulates the necessary methods so that evidence can be submitted, disputes can be settled and rulings can be set.

The Dispute Lifecycle is mostly absent for disputes created within the mocks. Once created they'll be open, existing indefinitely until the owner sets a ruling.

celest-helpers/contracts/mocks/MockArbitrator.sol API

instantiating

constructor(address)

Parameters:

• address _feeToken: Address of token to be used as fee for dispute creation.

Emitted Events:

The constructor does not emit any events

General function

Stores the _feeToken address in an immutable property and sets the instantiating address as the owner of this instance. Uses OpenZeppelin's Ownable API for ownership.

dispute creation

createDispute(uint256, bytes) -> (uint256)

Similar to a real arbitrator.createDispute call but it only stores the subject for the dispute, pulls the fee and emits a NewDispute event. Reverts if _possibleRulings is not 2.

submitting evidence

submitEvidence(uint256, address, bytes) -> ()

Virtually identical to a arbitrator.submitEvidence call. Exactly the same revert messages are issued if the caller is not the subject or if the dispute does not exist. Also emits the EvidenceSubmitted event.

closing the evidence period

closeEvidencePeriod(uint256) -> ()

Virtually identical to a arbitrator.closeEvidencePeriod call. Exactly the same revert messages are issued if the caller is not the subject or if the dispute does not exist. Also emits the EvidencePeriodClosed event. Only difference is it has no effect in terms of shortening the evidence phase.

retrieving a ruling

rule(uint256) -> (address, uint256)

Virtually identical to a arbitrator.rule call. Returns the subject and ruling if a ruling has been set. Emits a RulingComputed the first time a ruling is retrieved.

setting a ruling

setRuling(uint256, uint256) -> ()

Parameters:

• uint256 _disputeId: The dispute ID for which the ruling is to be set

• uint256 _ruling: Ruling ID (2 / 3 / 4)

Emitted events:

Does not emit any events.

General function

Reverts if:

• The dispute does not exist yet

• OR The caller is not the owner

• OR _ruling it not 2 / 3 / 4

Directly sets the ruling for a dispute. This is extremely in testing as you can directly simulate a ruling for your disputable contract without having to simulate a full jury selection, vote, appeal etc.

getters

getSubjectOf(uint256 _disputeId) -> (address subject)

getDisputeFees() -> (address recipient, IERC20 feeToken, uint256 feeAmount)

For the arbitrator mock the fee recipient will always be itself.

getDisputeManager() -> (address disputeManager)

Since the arbitrator mock is a 2-in-1 AragonCourt and DisputeManger it will return its own address.

Arbitrator Manifest Mock

Identical to the normal Arbitrator Manifest except it's only compatible with the AragonCourt / DisputeManager mock. The outward facing API is also identical.

Example

For a concrete example on how a test for a Disputable contract using the mocks looks like check out the test for the WorkAgreement contract described in the Getting Started section. The test can be found here.