LayerX Forge Std Integration, Test Mocks, and Solidity Test Support

Overview

The LayerX contract test suite uses vendored forge-std (v1.16.1) under lib/ for tests only. Production src/ has zero external imports. The test/mocks/ directory provides concrete mock contracts to simulate ERC-20 behavior, USDT-style approval rules, wrapped native flows, router execution, and reentrancy attacks.

Forge Std Configuration

Source: layerx/contracts/foundry.toml

Key	Value	Effect
`libs`	`["lib"]`	Resolves `forge-std` from `lib/`
`fs_permissions`	`read ./out`	Allows test file reads

The vendored forge-std package.json declares version 1.16.1.

Test Harness

forge-std/src/Test.sol is the abstract base contract combining TestBase, StdAssertions, StdChains, StdCheats, StdInvariant, and StdUtils. LayerX tests inherit from Test to access:

vm.deal / vm.prank / vm.startPrank for address impersonation
vm.expectRevert with stdError selectors
assertEq / assertTrue / assertGt for assertions
vm.load for direct storage reads
console2.log for decoded Forge trace logging

Test Mock Contracts

MockERC20

Source: layerx/contracts/test/mocks/MockERC20.sol

Standard, well-behaved ERC-20 test token.

Constructor	Type	Description
`n`	`string`	Token name
`s`	`string`	Token symbol
`d`	`uint8`	Decimals

Methods: mint(to, amount), transfer, approve, transferFrom (unlimited allowance when type(uint256).max).

MockUSDT

Source: layerx/contracts/test/mocks/MockUSDT.sol

Models non-standard USDT behavior:

transfer and transferFrom return void (no boolean)
approve requires resetting allowance to zero before setting a new non-zero value

Used to exercise SafeERC20.forceApprove and the no-boolean-return wrapper.

MockWrappedNative

Source: layerx/contracts/test/mocks/MockWrappedNative.sol

WETH-style wrapper inheriting MockERC20 ("Wrapped PAX", "WPAX9", 18 decimals). Methods: deposit() (accepts native value), withdraw(amount) (sends native value back).

MockPECORRouter

Source: layerx/contracts/test/mocks/MockPECORRouter.sol

Test DEX router for swap-based deposits.

Property	Type	Description
`usdl`	`IERC20`	Immutable USDL payout asset
`rateE18`	`mapping(address => uint256)`	Per-token conversion rate (scaled by 1e18)

Methods:

setRate(tokenIn, rate) - set conversion rate
swapBestRoute(tokenIn, tokenOut, amountIn, amountOutMin, deadline) - execute swap (requires USDL as tokenOut)
getBestQuote(tokenIn, tokenOut, amountIn) - read-only quote

Formula: out = amountIn * rateE18[tokenIn] / 1e18

ReentrantToken

Source: layerx/contracts/test/mocks/ReentrantToken.sol

Malicious token that attempts reentry during transferFrom. Inherits MockERC20 ("Reentrant", "RE", 6 decimals).

Property	Type	Description
`target`	`address`	Call target for reentry
`payload`	`bytes`	Calldata for reentry
`armed`	`bool`	Single-shot guard
`reentryAttempted`	`bool`	Whether callback was attempted
`reentrySucceeded`	`bool`	Whether callback succeeded

Methods:

arm(target, payload) - enable one-shot reentry attempt
transferFrom - when armed, clears arm, records attempt, calls target.call(payload), then continues with normal transfer

Used to prove that vault entrypoints are protected by nonReentrant.

Solidity Test Files

SettlementAnchor.t.sol

Tests: writer can anchor and root is visible via rootOf; non-writers rejected; same batch id cannot be recorded twice; zero roots rejected; governor can rotate writer.

SafeERC20.t.sol

Tests with a harness contract exposing library functions: standard transfers succeed; USDT-style no-boolean tokens accepted; forceApprove handles reset-to-zero; calling into non-contract address reverts.

LayerXVault.t.sol

Tests: direct USDL deposits mint 1:1; swap deposits enforce slippage/deadline; native deposits wrap and swap; settlement is idempotent/capped/reserve-bounded; force-exit covers initiate/challenge/finalize with epoch checks; pause/unpause obey access rules; governance is two-step; reentrancy guard blocks malicious tokens; exit-delay bounds enforced.

PaymentChannel.t.sol (Deus)

Tests: fund and payout, close and refund, availableWei accounting.

Fixture Files

File	Purpose
`lib/forge-std/test/fixtures/test.json`	JSON fixture with scalar + nested data
`lib/forge-std/test/fixtures/test.toml`	TOML mirror of JSON fixture
`lib/forge-std/test/fixtures/config.toml`	Chain-scoped config with typed subtables
`lib/forge-std/test/fixtures/broadcast.log.json`	Full broadcast record for parsing tests

Test Execution Pattern

1. Developer writes Solidity test inheriting Test
2. Test deploys mock contracts (MockERC20, MockUSDT, MockWrappedNative, MockPECORRouter, ReentrantToken)
3. Test calls vault/anchor methods with controlled mock state
4. Test asserts with assertEq / vm.expectRevert / vm.load
5. forge test --match-path test/ContractName.t.sol