mocks: add gasExhaust contract

src/mocks/malicious/gasExhaust.sol

@@ -0,0 +1,16 @@
+pragma solidity ^0.8.0;
+
+contract gasExhaust {
+    uint256 counter;
+    uint256 gasConsumeLimit;
+
+    function setGasConsumeLimit(uint256 _gasConsume) public {
+        gasConsumeLimit = _gasConsume;
+    }
+
+    fallback() external {
+        while (gasleft() > gasConsumeLimit) {
+            counter++;
+        }
+    }
+}

test/mocks/malicious/gasExhaust.t.sol

@@ -0,0 +1,25 @@
+pragma solidity ^0.8.0;
+
+import "forge-std/Test.sol";
+
+import {gasExhaust} from "../../../src/mocks/malicious/gasExhaust.sol";
+
+contract gasExhaustTest is Test {
+    gasExhaust public attacker;
+
+    function setUp() public {
+        attacker = new gasExhaust();
+    }
+
+    function testGasExhaustSuccess() public {
+        attacker.setGasConsumeLimit(6000);
+        (bool success, bytes memory returnData) = address(attacker).call{gas: 25000}("");
+        assertEq(success, true);
+    }
+
+    function testGasExhaustFail() public {
+        attacker.setGasConsumeLimit(100);
+        (bool success, bytes memory returnData) = address(attacker).call{gas: 25000}("");
+        assertEq(success, false);
+    }
+}