test double erc721 creation reverts

packages/contracts-bedrock/test/OptimismMintableERC20Factory.t.sol

@@ -42,7 +42,7 @@ contract OptimismMintableTokenFactory_Test is Bridge_Initializer {
         L2TokenFactory.createStandardL2Token(remote, "Beep", "BOOP");
     }
 
-    function test_createStandardL2Token_remoteIsZero_succeeds() external {
+    function test_createStandardL2Token_remoteIsZero_reverts() external {
         address remote = address(0);
         vm.expectRevert("OptimismMintableERC20Factory: must provide remote token address");
         L2TokenFactory.createStandardL2Token(remote, "Beep", "BOOP");

packages/contracts-bedrock/test/OptimismMintableERC721Factory.t.sol

@@ -53,6 +53,18 @@ contract OptimismMintableERC721Factory_Test is ERC721Bridge_Initializer {
         assertEq(created.REMOTE_CHAIN_ID(), 1);
     }
 
+    function test_createOptimismMintableERC721_sameTwice_reverts() external {
+        address remote = address(1234);
+
+        vm.prank(alice);
+        factory.createOptimismMintableERC721(remote, "L2Token", "L2T");
+
+        vm.expectRevert();
+
+        vm.prank(alice);
+        factory.createOptimismMintableERC721(remote, "L2Token", "L2T");
+    }
+
     function test_createOptimismMintableERC721_zeroRemoteToken_reverts() external {
         // Try to create a token with a zero remote token address.
         vm.expectRevert("OptimismMintableERC721Factory: L1 token address cannot be address(0)");