Update License

src/Error.sol

@@ -0,0 +1,16 @@
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity ^0.8.20;
+
+contract Error {
+    error NotAuthorized();
+
+    function throwError() external {
+        require(false, "not authorized");
+    }
+
+    function throwCustomError() external {
+        revert NotAuthorized();
+    }
+
+
+}

src/HelloWorld.sol

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: UNLICENSED
 pragma solidity ^0.8.20;
 
 contract HelloWorld {

src/Imports.sol

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: UNLICENSED
 pragma solidity ^0.8.20;
 
 import "solmate/tokens/ERC20.sol";

src/Wallet.sol

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: UNLICENSED
 pragma solidity ^0.8.20;
 
 contract Wallet {

test/Error.t.sol

@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity ^0.8.20;
+
+import "forge-std/Test.sol";
+import {Error} from "../src/Error.sol";
+
+contract ErrorTest is Test {
+    Error public err;
+
+    function setUp() public {
+        err = new Error();
+    }
+
+    function testFail() public {
+        err.throwError();
+    }
+
+    // Does the same test as above
+    function testRevert() public {
+        vm.expectRevert();
+        err.throwError();
+    }
+
+    // Test with require error message
+    function testRequireMessage() public {
+        vm.expectRevert(bytes("not authorized"));
+        err.throwError();
+    }
+
+    // Test custom error
+    function testCustomError() public {
+        vm.expectRevert(Error.NotAuthorized.selector);
+        err.throwCustomError();
+    }
+
+    // Test Error Label
+    function testErrorLabel() public {
+        assertEq(uint(1), uint(1), "test 1");
+        assertEq(uint(1), uint(1), "test 2");
+        assertEq(uint(1), uint(1), "test 3");
+        assertEq(uint(1), uint(1), "test 4");
+        // assertEq(uint(0), uint(2), "test 5");
+    }
+    
+}