Fix/add erc721 safe mint safe transfer from #1736 (#1816)

* added _safeTransferFrom function

* added safeMint functions

* added package-lock.json for consistency, don't know why it changes

* added initial suggestions/modifications

* change _safeTransferFrom to internal, reverted package-lock.json to original, and changed ERC721Pausable to override _transferFrom instead of transferFrom

* included tests for safeMint functions

* modified safeMint tests to be on ERC721Mock contract

* added safeMint to ERC721Mintable & respective test to ERC721MintBurn.behavior.js

test/token/ERC721/ERC721.behavior.js

@@ -4,6 +4,7 @@ const { ZERO_ADDRESS } = constants;
 const { shouldSupportInterfaces } = require('../../introspection/SupportsInterface.behavior');
 
 const ERC721ReceiverMock = artifacts.require('ERC721ReceiverMock.sol');
+const ERC721Mock = artifacts.require('ERC721Mock.sol');
 
 function shouldBehaveLikeERC721 (
   creator,
@@ -324,6 +325,68 @@ function shouldBehaveLikeERC721 (
       });
     });
 
+    describe('safe mint', function () {
+      const fourthTokenId = new BN(4);
+      const tokenId = fourthTokenId;
+      const data = '0x42';
+
+      beforeEach(async function () {
+        this.ERC721Mock = await ERC721Mock.new();
+      });
+
+      describe('via safeMint', function () { // regular minting is tested in ERC721Mintable.test.js and others
+        it('should call onERC721Received — with data', async function () {
+          this.receiver = await ERC721ReceiverMock.new(RECEIVER_MAGIC_VALUE, false);
+          const receipt = await this.ERC721Mock.safeMint(this.receiver.address, tokenId, data);
+
+          await expectEvent.inTransaction(receipt.tx, ERC721ReceiverMock, 'Received', {
+            from: ZERO_ADDRESS,
+            tokenId: tokenId,
+            data: data,
+          });
+        });
+
+        it('should call onERC721Received — without data', async function () {
+          this.receiver = await ERC721ReceiverMock.new(RECEIVER_MAGIC_VALUE, false);
+          const receipt = await this.ERC721Mock.safeMint(this.receiver.address, tokenId);
+
+          await expectEvent.inTransaction(receipt.tx, ERC721ReceiverMock, 'Received', {
+            from: ZERO_ADDRESS,
+            tokenId: tokenId,
+          });
+        });
+
+        context('to a receiver contract returning unexpected value', function () {
+          it('reverts', async function () {
+            const invalidReceiver = await ERC721ReceiverMock.new('0x42', false);
+            await expectRevert(
+              this.ERC721Mock.safeMint(invalidReceiver.address, tokenId),
+              'ERC721: transfer to non ERC721Receiver implementer'
+            );
+          });
+        });
+
+        context('to a receiver contract that throws', function () {
+          it('reverts', async function () {
+            const invalidReceiver = await ERC721ReceiverMock.new(RECEIVER_MAGIC_VALUE, true);
+            await expectRevert(
+              this.ERC721Mock.safeMint(invalidReceiver.address, tokenId),
+              'ERC721ReceiverMock: reverting'
+            );
+          });
+        });
+
+        context('to a contract that does not implement the required function', function () {
+          it('reverts', async function () {
+            const invalidReceiver = this.token;
+            await expectRevert.unspecified(
+              this.ERC721Mock.safeMint(invalidReceiver.address, tokenId)
+            );
+          });
+        });
+      });
+    });
+
     describe('approve', function () {
       const tokenId = firstTokenId;
 

test/token/ERC721/ERC721MintBurn.behavior.js

@@ -13,6 +13,7 @@ function shouldBehaveLikeMintAndBurnERC721 (
   const thirdTokenId = new BN(3);
   const unknownTokenId = new BN(4);
   const MOCK_URI = 'https://example.com';
+  const data = '0x42';
 
   describe('like a mintable and burnable ERC721', function () {
     beforeEach(async function () {
@@ -72,6 +73,18 @@ function shouldBehaveLikeMintAndBurnERC721 (
       });
     });
 
+    describe('safeMint', function () {
+      it('it can safely mint with data', async function () {
+        await this.token.methods['safeMint(address,uint256,bytes)'](...[newOwner, thirdTokenId, data],
+          { from: minter });
+      });
+
+      it('it can safely mint without data', async function () {
+        await this.token.methods['safeMint(address,uint256)'](...[newOwner, thirdTokenId],
+          { from: minter });
+      });
+    });
+
     describe('burn', function () {
       const tokenId = firstTokenId;
       let logs = null;