Remove enumerable from ERC721 and add an ERC721Enumerable extension (#2511)

Co-authored-by: Francisco Giordano <frangio.1@gmail.com>

contracts/mocks/ERC721EnumerableMock.sol

@@ -0,0 +1,43 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.0;
+
+import "../token/ERC721/ERC721Enumerable.sol";
+
+/**
+ * @title ERC721Mock
+ * This mock just provides a public safeMint, mint, and burn functions for testing purposes
+ */
+contract ERC721EnumerableMock is ERC721Enumerable {
+    string private _baseTokenURI;
+
+    constructor (string memory name, string memory symbol) ERC721(name, symbol) { }
+
+    function _baseURI() internal view virtual override returns (string memory) {
+        return _baseTokenURI;
+    }
+
+    function setBaseURI(string calldata newBaseTokenURI) public {
+        _baseTokenURI = newBaseTokenURI;
+    }
+
+    function baseURI() public view returns (string memory) {
+        return _baseURI();
+    }
+
+    function mint(address to, uint256 tokenId) public {
+        _mint(to, tokenId);
+    }
+
+    function safeMint(address to, uint256 tokenId) public {
+        _safeMint(to, tokenId);
+    }
+
+    function safeMint(address to, uint256 tokenId, bytes memory _data) public {
+        _safeMint(to, tokenId, _data);
+    }
+
+    function burn(uint256 tokenId) public {
+        _burn(tokenId);
+    }
+}

contracts/mocks/ERC721Mock.sol

@@ -9,20 +9,26 @@ import "../token/ERC721/ERC721.sol";
  * This mock just provides a public safeMint, mint, and burn functions for testing purposes
  */
 contract ERC721Mock is ERC721 {
+    string private _baseTokenURI;
+
     constructor (string memory name, string memory symbol) ERC721(name, symbol) { }
 
+    function _baseURI() internal view virtual override returns (string memory) {
+        return _baseTokenURI;
+    }
+
+    function setBaseURI(string calldata newBaseTokenURI) public {
+        _baseTokenURI = newBaseTokenURI;
+    }
+
+    function baseURI() public view returns (string memory) {
+        return _baseURI();
+    }
+
     function exists(uint256 tokenId) public view returns (bool) {
         return _exists(tokenId);
     }
 
-    function setTokenURI(uint256 tokenId, string memory uri) public {
-        _setTokenURI(tokenId, uri);
-    }
-
-    function setBaseURI(string memory baseURI) public {
-        _setBaseURI(baseURI);
-    }
-
     function mint(address to, uint256 tokenId) public {
         _mint(to, tokenId);
     }