tests: invariant balance operator

Author: geolffreym

test/finance/TrustlessEscrow.sol

@@ -0,0 +1,95 @@
+// SPDX-License-Identifier: BUSL-1.1
+pragma solidity 0.8.26;
+
+import "forge-std/Test.sol";
+
+import { IERC20 } from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
+import { ITollgate } from "@synaps3/core/interfaces/economics/ITollgate.sol";
+import { ILedgerVault } from "@synaps3/core/interfaces/financial/ILedgerVault.sol";
+import { IAgreementManager } from "@synaps3/core/interfaces/financial/IAgreementManager.sol";
+import { IAgreementSettler } from "@synaps3/core/interfaces/financial/IAgreementSettler.sol";
+import { BaseTest } from "test/BaseTest.t.sol";
+import { T } from "contracts/core/primitives/Types.sol";
+import { C } from "contracts/core/primitives/Constants.sol";
+
+contract MockArbiter {
+    IAgreementSettler public immutable AGREEMENT_SETTLER;
+
+    constructor(address agreementSettler) {
+        AGREEMENT_SETTLER = IAgreementSettler(agreementSettler);
+    }
+
+    function executeAgreement(uint256 proof, address counterparty) external returns (T.Agreement memory agreement) {
+        agreement = AGREEMENT_SETTLER.settleAgreement(proof, counterparty);
+    }
+}
+
+contract TrustlessEscrowTest is BaseTest {
+    MockArbiter arbiter;
+
+    function setUp() public initialize {
+        deployAgreementSettler();
+        arbiter = MockArbiter(agreementSettler);
+
+        uint256 fees = 500; // 5%
+        vm.prank(governor);
+        ITollgate(tollgate).setFees(T.Scheme.BPS, address(arbiter), fees, token);
+
+        vm.startPrank(admin);
+
+        uint256 amount = 100 * 1e18;
+        IERC20(token).approve(ledger, amount);
+        ILedgerVault(ledger).deposit(user, amount, token);
+        vm.stopPrank();
+    }
+
+    function test_PreviewAgreement_ReturnExpectedAgreement() public {
+        uint256 amount = 10 * 1e18;
+        IAgreementManager manager = IAgreementManager(agreementManager);
+        (uint256 feesBPS, ) = ITollgate(tollgate).getFees(address(arbiter),token);
+
+        address[] memory parties = new address[](2);
+        parties[0] = vm.addr(1);
+        parties[1] = vm.addr(2);
+
+        vm.prank(user);
+        T.Agreement memory agreement = manager.previewAgreement(amount, token, address(arbiter), parties, "");
+        uint256 fees = (feesBPS * amount) / 10_000; // 5% configured
+
+        assertEq(agreement.total, amount);
+        assertEq(agreement.initiator, user);
+        assertEq(agreement.fees, fees);
+        assertEq(agreement.locked, amount); // eq amount if not exceed allowed parties
+        assertEq(agreement.currency, token);
+        assertEq(agreement.arbiter, address(arbiter));
+        assertEq(agreement.parties, parties);
+        assertEq(agreement.payload, "");
+    }
+
+    function testFuzz_PreviewAgreement_ReturnPenalizedAgreement(uint256 partiesLen) public {
+        uint256 amount = 100 * 1e18;
+        // max 18 are allowed with soft cap maxParties = 5
+        // force penalization with min 6, maxParties + 13 = 18
+        uint256 capped = bound(partiesLen, 6, 18); 
+        IAgreementManager manager = IAgreementManager(agreementManager);
+
+        // max is 5, per each extra 1% in accumulated succession,
+        // eg: 6, 7, 8 = 1 + 2 + 3 = 6% penalization
+        address[] memory parties = new address[](capped);
+        for (uint256 i = 0; i < capped; i++) {
+            parties[i] = vm.addr(i + 1);
+        }
+
+        T.Agreement memory agreement = manager.previewAgreement(amount, token, address(arbiter), parties, "");
+
+        uint256 exceed = capped - 5; // default maxParties = 5;
+        uint256 expectedPercentage = (exceed * (exceed + 1)) / 2;
+        uint256 expectedPenalizationBPS = expectedPercentage * 100;
+        uint256 expectedPenalizationAmount = (amount * expectedPenalizationBPS) / C.BPS_MAX;
+        uint256 expectedLocked = amount + expectedPenalizationAmount;
+
+        assertEq(agreement.total, amount);
+        assertEq(agreement.locked, expectedLocked);
+        assertEq(agreement.parties, parties);
+    }
+}