From c49c0e595516720ba878cf5b6bbf3e03a4031b69 Mon Sep 17 00:00:00 2001
From: Yash <kumaryashcse@gmail.com>
Date: Tue, 20 Sep 2022 18:59:44 +0530
Subject: [PATCH] (Q-3) TokenERC721 can have empty URI

---
 contracts/token/TokenERC721.sol  | 1 +
 src/test/token/TokenERC721.t.sol | 7 +++++++
 2 files changed, 8 insertions(+)

diff --git a/contracts/token/TokenERC721.sol b/contracts/token/TokenERC721.sol
index 84065bec7..74f431e6a 100644
--- a/contracts/token/TokenERC721.sol
+++ b/contracts/token/TokenERC721.sol
@@ -305,6 +305,7 @@ contract TokenERC721 is
         tokenIdToMint = nextTokenIdToMint;
         nextTokenIdToMint += 1;
 
+        require(bytes(_uri).length > 0, "empty uri.");
         uri[tokenIdToMint] = _uri;
 
         _safeMint(_to, tokenIdToMint);
diff --git a/src/test/token/TokenERC721.t.sol b/src/test/token/TokenERC721.t.sol
index 75fe2daa8..3253c259b 100644
--- a/src/test/token/TokenERC721.t.sol
+++ b/src/test/token/TokenERC721.t.sol
@@ -307,6 +307,13 @@ contract TokenERC721Test is BaseTest {
         tokenContract.mintTo(recipient, _tokenURI);
     }
 
+    function test_revert_mintTo_emptyURI() public {
+        // mint
+        vm.prank(deployerSigner);
+        vm.expectRevert("empty uri.");
+        tokenContract.mintTo(recipient, "");
+    }
+
     function test_event_mintTo() public {
         string memory _tokenURI = "tokenURI";