feat: add token-price example

Author: wsdt

contracts/test/TestTokenPrice.sol

@@ -0,0 +1,32 @@
+// SPDX-License-Identifier: GPL-3.0
+pragma solidity ^0.8.12;
+
+import "../samples/HybridAccount.sol";
+
+contract TestTokenPrice {
+    mapping(uint256 => uint256) public counters;
+    address payable immutable helperAddr;
+
+    constructor(address payable _helperAddr) {
+        helperAddr = _helperAddr;
+        counters[0] = 100;
+    }
+
+    function fetchPrice(
+        string calldata token
+    ) public returns (string memory) {
+        HybridAccount ha = HybridAccount(payable(helperAddr));
+        string memory price;
+
+        bytes memory req = abi.encodeWithSignature("getprice(string)", token);
+        bytes32 userKey = bytes32(abi.encode(msg.sender));
+        (uint32 error, bytes memory ret) = ha.CallOffchain(userKey, req);
+
+        if (error != 0) {
+            revert(string(ret));
+        }
+
+        (price) = abi.decode(ret, (string));
+        return price;
+    }
+}