Remove unnecessary internal functions, max out test coverage

contracts/ERC721A.sol

@@ -820,41 +820,6 @@ contract ERC721A is IERC721A {
         }
     }
 
-    /**
-     * @dev Equivalent to `_safeBatchTransferFrom(from, to, tokenIds)`.
-     */
-    function _safeBatchTransferFrom(
-        address from,
-        address to,
-        uint256[] memory tokenIds
-    ) internal virtual {
-        _safeBatchTransferFrom(address(0), from, to, tokenIds);
-    }
-
-    /**
-     * @dev Equivalent to `_safeBatchTransferFrom(by, from, to, tokenIds, '')`.
-     */
-    function _safeBatchTransferFrom(
-        address by,
-        address from,
-        address to,
-        uint256[] memory tokenIds
-    ) internal virtual {
-        _safeBatchTransferFrom(by, from, to, tokenIds, '');
-    }
-
-    /**
-     * @dev Equivalent to `_safeBatchTransferFrom(address(0), from, to, tokenIds, _data)`.
-     */
-    function _safeBatchTransferFrom(
-        address from,
-        address to,
-        uint256[] memory tokenIds,
-        bytes memory _data
-    ) internal virtual {
-        _safeBatchTransferFrom(address(0), from, to, tokenIds, _data);
-    }
-
     /**
      * @dev Safely transfers `tokenIds` in batch from `from` to `to`.
      *
@@ -1375,13 +1340,6 @@ contract ERC721A is IERC721A {
         }
     }
 
-    /**
-     * @dev Equivalent to `_batchBurn(address(0), tokenIds)`.
-     */
-    function _batchBurn(uint256[] memory tokenIds) internal virtual {
-        _batchBurn(address(0), tokenIds);
-    }
-
     /**
      * @dev Destroys `tokenIds`.
      * Approvals are not cleared when tokenIds are burned.

contracts/mocks/ERC721ABatchBurnableMock.sol

@@ -37,14 +37,4 @@ contract ERC721ABatchBurnableMock is ERC721ABatchBurnable, DirectBurnBitSetterHe
     function initializeOwnershipAt(uint256 index) public {
         _initializeOwnershipAt(index);
     }
-
-    function batchBurnUnoptimized(uint256[] memory tokenIds) public {
-        unchecked {
-            uint256 tokenId;
-            for (uint256 i; i < tokenIds.length; ++i) {
-                tokenId = tokenIds[i];
-                _burn(tokenId);
-            }
-        }
-    }
 }

contracts/mocks/ERC721ABatchTransferableMock.sol

@@ -9,10 +9,6 @@ import '../extensions/ERC721ABatchTransferable.sol';
 contract ERC721ABatchTransferableMock is ERC721ABatchTransferable {
     constructor(string memory name_, string memory symbol_) ERC721A(name_, symbol_) {}
 
-    function exists(uint256 tokenId) public view returns (bool) {
-        return _exists(tokenId);
-    }
-
     function safeMint(address to, uint256 quantity) public {
         _safeMint(to, quantity);
     }
@@ -21,22 +17,6 @@ contract ERC721ABatchTransferableMock is ERC721ABatchTransferable {
         return _ownershipAt(index);
     }
 
-    function totalMinted() public view returns (uint256) {
-        return _totalMinted();
-    }
-
-    function totalBurned() public view returns (uint256) {
-        return _totalBurned();
-    }
-
-    function numberBurned(address owner) public view returns (uint256) {
-        return _numberBurned(owner);
-    }
-
-    function burn(uint256 tokenId) public {
-        _burn(tokenId, true);
-    }
-
     function initializeOwnershipAt(uint256 index) public {
         _initializeOwnershipAt(index);
     }
@@ -59,10 +39,8 @@ contract ERC721ABatchTransferableMock is ERC721ABatchTransferable {
         uint256[] memory tokenIds
     ) public {
         unchecked {
-            uint256 tokenId;
-            for (uint256 i; i < tokenIds.length; ++i) {
-                tokenId = tokenIds[i];
-                transferFrom(from, to, tokenId);
+            for (uint256 i; i != tokenIds.length; ++i) {
+                transferFrom(from, to, tokenIds[i]);
             }
         }
     }
@@ -75,4 +53,12 @@ contract ERC721ABatchTransferableMock is ERC721ABatchTransferable {
     ) public {
         _batchTransferFrom(by, from, to, tokenIds);
     }
+
+    function directBatchTransferFrom(
+        address from,
+        address to,
+        uint256[] memory tokenIds
+    ) public {
+        _batchTransferFrom(from, to, tokenIds);
+    }
 }

test/GasUsage.test.js

@@ -40,6 +40,22 @@ describe('ERC721A Gas Usage', function () {
     });
   });
 
+  context('mintHundred', function () {
+    it('runs mintHundred 2 times', async function () {
+      for (let i = 0; i < 2; i++) {
+        await this.erc721a.mintHundred(this.addr1.address);
+      }
+    });
+  });
+
+  context('safeMintHundred', function () {
+    it('runs safeMintHundred 2 times', async function () {
+      for (let i = 0; i < 2; i++) {
+        await this.erc721a.safeMintHundred(this.addr1.address);
+      }
+    });
+  });
+
   context('transferFrom', function () {
     beforeEach(async function () {
       await this.erc721a.mintTen(this.owner.address);

test/extensions/ERC721ABatchBurnable.test.js

@@ -62,6 +62,10 @@ const createTestSuite = ({ contract, constructorArgs }) =>
         });
       });
 
+      it('batch burn nothing', async function () {
+        await this.erc721aBatchBurnable.connect(this.addr1).batchBurn([]);
+      });
+
       it('changes numberBurned', async function () {
         expect(await this.erc721aBatchBurnable.numberBurned(this.addr1.address)).to.equal(this.totalBurned);
         await this.erc721aBatchBurnable.connect(this.addr1).batchBurn([this.notBurnedTokenId4]);

test/extensions/ERC721ABatchTransferable.test.js

@@ -59,6 +59,20 @@ const createTestSuite = ({ contract, constructorArgs }) =>
         await this.erc721aBatchTransferable['safeMint(address,uint256)'](this.addr3.address, 7);
       });
 
+      it('test safe batch transfer with data', async function () {
+        const transferFn = 'safeBatchTransferFrom(address,address,uint256[],bytes)';
+        const tokensToTransfer = this.addr1.expected.tokens;
+        await expect(this.erc721aBatchTransferable.connect(this.addr1)[transferFn](
+          this.addr1.address, this.receiver.address, tokensToTransfer, '0x01'
+        )).to.be.revertedWith('reverted in the receiver contract!');
+      });
+
+      it('batch transfer nothing', async function () {
+        const transferFn = 'safeBatchTransferFrom(address,address,uint256[])';
+        await this.erc721aBatchTransferable.connect(this.addr1)[transferFn](
+          this.addr1.address, this.receiver.address, []);
+      });
+
       context('test batch transfer functionality', function () {
         const testSuccessfulBatchTransfer = function (transferFn, transferToContract = true) {
           describe('successful transfers', async function () {
@@ -93,8 +107,8 @@ const createTestSuite = ({ contract, constructorArgs }) =>
               // Transfer part of uninitialized tokens
               this.tokensToTransferAlt = [25, 26, 27];
               this.transferTxAlt = await this.erc721aBatchTransferable.connect(this.addr3)[transferFn](
-              this.addr3.address, this.addr5.address, this.tokensToTransferAlt
-            );
+                this.addr3.address, this.addr5.address, this.tokensToTransferAlt
+              );
             });
 
             it('emits Transfers event', async function () {
@@ -383,14 +397,18 @@ const createTestSuite = ({ contract, constructorArgs }) =>
               await this.erc721aBatchTransferable.connect(this.addr2).setApprovalForAll(this.sender.address, true);
               await expect(
                 this.erc721aBatchTransferable
-                .connect(this.sender)['directBatchTransferFrom'](
+                .connect(this.sender)['directBatchTransferFrom(address,address,address,uint256[])'](
                   ZERO_ADDRESS, ZERO_ADDRESS, this.sender.address, this.tokenIds
                 )
               ).to.be.revertedWith('TransferFromIncorrectOwner');
               this.erc721aBatchTransferable
-              .connect(this.sender)['directBatchTransferFrom'](
+              .connect(this.sender)['directBatchTransferFrom(address,address,address,uint256[])'](
                 ZERO_ADDRESS, this.addr2.address, this.sender.address, this.tokenIds
               );
+              this.erc721aBatchTransferable
+              .connect(this.addr2)['directBatchTransferFrom(address,address,uint256[])'](
+                this.sender.address, this.addr2.address, this.tokenIds
+              );
             });
 
             it('rejects transfer to zero address', async function () {
@@ -478,6 +496,7 @@ const createTestSuite = ({ contract, constructorArgs }) =>
               testApproveBatchTransfer(fn, false);
             });
           });
+
           context('safeBatchTransferFrom', function (fn = 'safeBatchTransferFrom(address,address,uint256[])') {
             describe('to contract', function () {
               testSuccessfulBatchTransfer(fn);