feat: Invariant helpers and mockVRF (#26)

* feat: Invariant helpers and mockVRF

* fix: Lockfile

* fix: Update prettier command

---------

Co-authored-by: Hiroshi <[email protected]>

package.json

@@ -18,8 +18,8 @@
   "scripts": {
     "compile": "hardhat compile",
     "compile:force": "hardhat compile --force",
-    "format:check": "prettier --check '**/*.{js,jsx,ts,tsx,sol,json,yaml,md}'",
-    "format:write": "prettier --write '**/*.{js,jsx,ts,tsx,json,yaml,md}'",
+    "format:check": "npx prettier --check '**/*.{js,jsx,ts,tsx,sol,json,yaml,md}'",
+    "format:write": "npx prettier --write '**/*.{js,jsx,ts,tsx,sol,json,yaml,md}'",
     "lint": "eslint '**/*.{js,jsx,ts,tsx}'",
     "prepare": "husky install",
     "test": "hardhat test",
@@ -67,6 +67,7 @@
     "typescript": "^4.5.2"
   },
   "dependencies": {
+    "@chainlink/contracts": "^0.6.1",
     "@looksrare/contracts-libs": "^3.1.0"
   }
 }

test/foundry/InvariantTestHelpers.sol

@@ -0,0 +1,40 @@
+// SPDX-License-Identifier: MIT
+pragma solidity 0.8.20;
+
+import {CommonBase} from "forge-std/Base.sol";
+import {StdCheats} from "forge-std/StdCheats.sol";
+import {StdUtils} from "forge-std/StdUtils.sol";
+
+contract InvariantTestHelpers is CommonBase, StdCheats, StdUtils {
+    address[100] internal actors;
+    address internal currentActor;
+    bool internal callsMustBeValid;
+    mapping(bytes => uint256) internal calls;
+
+    constructor() {
+        _populateActors();
+        _setCallsMustBeValid();
+    }
+
+    modifier useActor(uint256 actorIndexSeed) {
+        currentActor = actors[bound(actorIndexSeed, 0, 99)];
+        vm.startPrank(currentActor);
+        _;
+        vm.stopPrank();
+    }
+
+    modifier countCall(bytes memory key) {
+        calls[key]++;
+        _;
+    }
+
+    function _populateActors() internal {
+        for (uint256 i; i < 100; i++) {
+            actors[i] = address(uint160(uint256(keccak256(abi.encodePacked(i)))));
+        }
+    }
+
+    function _setCallsMustBeValid() internal {
+        callsMustBeValid = vm.envBool("FOUNDRY_INVARIANT_FAIL_ON_REVERT");
+    }
+}

test/mock/MockVRFCoordinatorV2.sol

@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: MIT
+pragma solidity 0.8.20;
+
+import {VRFConsumerBaseV2} from "@chainlink/contracts/src/v0.8/VRFConsumerBaseV2.sol";
+
+contract MockVRFCoordinatorV2 {
+    VRFConsumerBaseV2 public vrfConsumerBaseV2;
+    uint256 public requestCount;
+    uint256[] public requestIds;
+
+    function setVRFConsumerBaseV2(address _vrfConsumerBaseV2) external {
+        vrfConsumerBaseV2 = VRFConsumerBaseV2(_vrfConsumerBaseV2);
+    }
+
+    function requestRandomWords(
+        bytes32 keyHash,
+        uint64 subId,
+        uint16 requestConfirmations,
+        uint32 callbackGasLimit,
+        uint32 numWords
+    ) external returns (uint256 requestId) {
+        requestId = uint256(
+            keccak256(abi.encodePacked(keyHash, subId, requestConfirmations, callbackGasLimit, numWords, requestCount))
+        );
+        requestIds.push(requestId);
+        requestCount++;
+    }
+
+    function fulfillRandomWords(uint256 randomWord) external returns (uint256 requestId) {
+        uint256 requestsInQueue = requestIds.length;
+        if (requestsInQueue == 0) {
+            return 0;
+        }
+
+        requestId = requestIds[requestsInQueue - 1];
+        if (requestId == 0) return requestId;
+
+        uint256[] memory randomWords = new uint256[](1);
+        randomWords[0] = randomWord;
+
+        vrfConsumerBaseV2.rawFulfillRandomWords(requestId, randomWords);
+
+        requestIds.pop();
+    }
+}