Change behavior of unwrap to preserve wrapped token URI (#170)

Author: joaquim-verges

contracts/feature/TokenBundle.sol

@@ -66,6 +66,9 @@ abstract contract TokenBundle is ITokenBundle {
 
     /// @dev Lets the calling contract delete a particular bundle.
     function _deleteBundle(uint256 _bundleId) internal {
-        delete bundle[_bundleId];
+        for (uint256 i = 0; i < bundle[_bundleId].count; i += 1) {
+            delete bundle[_bundleId].tokens[i];
+        }
+        bundle[_bundleId].count = 0;
     }
 }

src/test/Multiwrap.t.sol

@@ -489,7 +489,8 @@ contract MultiwrapTest is BaseTest {
         vm.expectRevert("ERC721: owner query for nonexistent token");
         multiwrap.ownerOf(expectedIdForWrappedToken);
 
-        assertEq("", multiwrap.tokenURI(expectedIdForWrappedToken));
+        assertEq(uriForWrappedToken, multiwrap.tokenURI(expectedIdForWrappedToken));
+        assertEq(0, multiwrap.getTokenCountOfBundle(expectedIdForWrappedToken));
 
         ITokenBundle.Token[] memory contentsOfWrappedToken = multiwrap.getWrappedContents(expectedIdForWrappedToken);
         assertEq(contentsOfWrappedToken.length, 0);
@@ -519,7 +520,8 @@ contract MultiwrapTest is BaseTest {
         vm.expectRevert("ERC721: owner query for nonexistent token");
         multiwrap.ownerOf(expectedIdForWrappedToken);
 
-        assertEq("", multiwrap.tokenURI(expectedIdForWrappedToken));
+        assertEq(uriForWrappedToken, multiwrap.tokenURI(expectedIdForWrappedToken));
+        assertEq(0, multiwrap.getTokenCountOfBundle(expectedIdForWrappedToken));
 
         ITokenBundle.Token[] memory contentsOfWrappedToken = multiwrap.getWrappedContents(expectedIdForWrappedToken);
         assertEq(contentsOfWrappedToken.length, 0);
@@ -750,7 +752,8 @@ contract MultiwrapTest is BaseTest {
         vm.expectRevert("ERC721: owner query for nonexistent token");
         multiwrap.ownerOf(expectedIdForWrappedToken);
 
-        assertEq("", multiwrap.tokenURI(expectedIdForWrappedToken));
+        assertEq(uriForWrappedToken, multiwrap.tokenURI(expectedIdForWrappedToken));
+        assertEq(0, multiwrap.getTokenCountOfBundle(expectedIdForWrappedToken));
 
         ITokenBundle.Token[] memory contentsOfWrappedToken = multiwrap.getWrappedContents(expectedIdForWrappedToken);
         assertEq(contentsOfWrappedToken.length, 0);