Unit Test

Generate Foundry unit tests for a specific contract following this repository's established directory layout, inheritance chain, setup order, and test naming rules.

1. Directory layout

contracts/tests/unit/<category>/<ContractName>/
├── shared/
│   └── Shared.sol
├── concrete/
│   ├── FunctionA.t.sol
│   ├── FunctionB.t.sol
│   └── ViewFunctions.t.sol
└── fuzz/
    ├── FunctionA.fuzz.t.sol
    └── FunctionB.fuzz.t.sol

Rules:

• one file per public or external state-changing function
• view and pure functions may be grouped in ViewFunctions.t.sol
• admin and setter functions may be grouped in Admin.t.sol or Config.t.sol

2. Inheritance chain

forge-std/Test
  └─ Base
       └─ Unit_Shared_Test
            ├─ Unit_Concrete_<Contract>_<Feature>_Test
            └─ Unit_Fuzz_<Contract>_<Feature>_Test

Base owns shared actors, constants, and IERC20 external token refs. All typed contract/proxy/mock state variables are declared in each Shared.t.sol file (not in Base). This keeps Base lightweight so changes don't invalidate the entire Forge cache.

Interface-only testing

Tests must interact with contracts through interfaces, not concrete implementations. See contracts/tests/README.md for full details.

Available interfaces:

Interface	File	Used for
IVault	contracts/interfaces/IVault.sol	All vault contracts
IOToken	contracts/interfaces/IOToken.sol	All rebasing tokens (OUSD, OETH, OETHBase)
IWOToken	contracts/interfaces/IWOToken.sol	All wrapped tokens (WOETH, WOETHBase, WOETHPlume, WrappedOusd)
IProxy	contracts/interfaces/IProxy.sol	All proxy instances
Strategy interfaces	contracts/interfaces/strategies/	Per-strategy interfaces (ICurveAMOStrategy, ICompoundingStakingStrategy, etc.)

Key rules:

• import interfaces, not concrete contracts
• declare state variables with interface types
• deploy with vm.deployCode instead of new (except mocks), and always reference artifact paths through tests/utils/Artifacts.sol (e.g. vm.deployCode(Vaults.OUSD, abi.encode(address(usdc)))); add the entry to the relevant sub-library if it does not exist yet
• reference events from the interface: emit IVault.CapitalPaused();
• access struct return values by field name: vault.withdrawalQueueMetadata().claimable

Product-specific vault types

Product	Token	Vault	Artifacts reference
OUSD	OUSD	OUSDVault	Vaults.OUSD
OETH	OETH	OETHVault	Vaults.OETH
OETHBase	OETHBase	OETHBaseVault	Vaults.OETH_BASE

Add the entry to tests/utils/Artifacts.sol if it does not exist yet.

3. Shared setup contract

shared/Shared.sol should keep setup in this order:

function setUp() public virtual override {
    super.setUp();
    vm.warp(7 days);
    _deployMockContracts();
    _deployContracts();
    _configureContracts();
    _fundInitialUsers();
    label();
}

Key rules:

• deploy implementations with vm.deployCode, then proxies with vm.deployCode(Proxies.IG_PROXY); all artifact paths (including the proxy) come from tests/utils/Artifacts.sol — never inline a "contracts/...sol:Name" string in a test file
• initialize proxies via proxy.initialize(impl, governor, initData)
• cast proxies to interface types: ousd = IOToken(address(ousdProxy))
• use vm.startPrank(governor) for config blocks
• put labels at the end
• gotcha: vm.deployCode loads from compiled artifacts; always run forge build contracts/ before forge test after modifying contract source

Mocks:

• test-only mocks belong under tests/mocks/
• existing production mocks under contracts/mocks/ should usually be extended in place

4. Concrete test naming

File and contract naming:

concrete/RebaseOptIn.t.sol
Unit_Concrete_<ContractName>_RebaseOptIn_Test

Function naming patterns:

• test_<function>()
• test_<function>_<behavior>()
• test_<function>_RevertWhen_<condition>()
• test_<function>_emits<EventName>()

Casing rules:

• function, behavior, and condition stay camelCase
• RevertWhen is the only PascalCase token in the test name

Use exact revert strings with vm.expectRevert("...").

Emit events from interfaces, not concrete contracts:

vm.expectEmit(true, true, true, true);
emit IVault.EventName(arg1, arg2);

5. Fuzz tests

Contract name pattern:

Unit_Fuzz_<ContractName>_<Feature>_Test

Function pattern:

/// @notice Plain-English property description
function testFuzz_<function>_<property>(...) public { ... }

Rules:

• always prefer bound() over vm.assume()
• use assertEq for exact math
• use assertApproxEqAbs where rounding is expected
• focus on strong properties rather than sheer volume

Typical ranges in this repo:

• USDC: bound(amount, 1, 1e12)
• OUSD: bound(amount, 1e12, 100e18)
• basis points: bound(bps, 1, 5000)
• bounded yield: bound(yield_, 1, 3e5)

6. Foundry config expectations

Match the repository's fuzz configuration in contracts/foundry.toml when relevant. Keep tests deterministic and consistent with existing suite conventions.

Output expectations

When implementing tests:

• use interface-only imports; no concrete contract imports except mocks
• deploy contracts with vm.deployCode, not new (mocks are fine with new), and reference all artifact paths through tests/utils/Artifacts.sol — no inline "contracts/...sol:Name" strings
• mirror the existing local test style before inventing new patterns
• prefer coverage that matches real business logic paths over cosmetic line coverage
• add both concrete and fuzz coverage when the function has stateful logic or arithmetic properties
• keep new helpers in Shared.sol rather than duplicating setup across test files