Add upgradeable ERC721 SeaDrop proxy tests

src-upgradeable/README.md

@@ -28,6 +28,19 @@ Located at [`scripts/deploy.ts`](./scripts/deploy.ts)
 
 Located at [`scripts/upgrade.ts`](./scripts/upgrade.ts)
 
+## Testing
+
+The upgradeable package now ships with a dedicated Hardhat test suite that
+exercises the proxy workflow and SeaDrop integration mirrors. From the project
+root execute:
+
+```
+yarn test:upgradeable
+```
+
+This command uses `src-upgradeable/hardhat.config.ts`, deploys mocks, and
+verifies that upgradeable tokens retain configuration through proxy upgrades.
+
 ### Testnet / Mainnet
 
 We will use the Sepolia testnet as an example.

src-upgradeable/hardhat.config.ts

@@ -28,5 +28,5 @@ module.exports = {
     // Obtain one at https://etherscan.io/
     apiKey: process.env.ETHERSCAN_API_KEY,
   },
-  paths: { sources: "./src" },
+  paths: { sources: "./src", tests: "./test" },
 };

src-upgradeable/src/mocks/ERC721SeaDropUpgradeableV2.sol

@@ -0,0 +1,14 @@
+// SPDX-License-Identifier: MIT
+pragma solidity 0.8.17;
+
+import "../ERC721SeaDropUpgradeable.sol";
+
+/**
+ * @dev Simple extension of ERC721SeaDropUpgradeable used to verify upgrade
+ *      safety during testing.
+ */
+contract ERC721SeaDropUpgradeableV2 is ERC721SeaDropUpgradeable {
+    function version() external pure returns (string memory) {
+        return "ERC721SeaDropUpgradeable_V2";
+    }
+}