test(ContractTest): add fuzzing example

Author: fubuloubu

tests/integration/soliditytests/test_fuzzing.sol

@@ -0,0 +1,17 @@
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity ^0.8;
+
+import {IERC20} from "openzeppelin/contracts/token/ERC20/IERC20.sol";
+
+contract FuzzTest {
+    /// @custom:ape-fuzzer-max-examples 200
+    function test_with_fuzzing(uint256 a) external {
+        require(a != 29678634502528050652056023465820843, "Found a rare bug!");
+    }
+
+    /// @custom:ape-fuzz-deadline 1000
+    function test_token_approvals(IERC20 token, uint256 amount) external {
+        require(token.approve(msg.sender, amount));
+        require(token.allowance(address(this), msg.sender) == amount);
+    }
+}

tests/integration/vypertests/test_fuzzing.vy

@@ -0,0 +1,13 @@
+from ethereum.ercs import IERC20
+
+@external
+def test_with_fuzzing(a: uint256):
+    """@custom:ape-fuzzer-max-examples 200"""
+    assert a != 29678634502528050652056023465820843, "Found a rare bug!"
+
+
+@external
+def test_token_approvals(token: IERC20, amount: uint256):
+    """@custom:ape-fuzz-deadline 1000"""
+    assert extcall token.approve(msg.sender, amount)
+    assert staticcall token.allowance(self, msg.sender) == amount