✨ Add airdrop functionality

src/ProtoGravaNFT.sol

@@ -320,17 +320,27 @@ contract ProtoGravaNFT is ERC721, LilENS, LilOwnable, LilHash {
 
     /* solhint-enable quotes */
 
+    /// @notice Airdrop a token
+    function airdrop(address to) external onlyContractOwner {
+        mintTo(to);
+    }
+
     /// @notice Mint a token
     function mint() external onlyWhenPublicMintEnabled {
+        mintTo(msg.sender);
+    }
+
+    /// @notice Mint a token to an address
+    function mintTo(address to) internal {
         if (totalMinted + 1 >= MAX_TOTAL_MINTED) revert NoTokensLeft();
 
-        if (balanceOf(msg.sender) > 0) revert OnePerUser();
+        if (balanceOf(to) > 0) revert OnePerUser();
 
         uint256 newItemId = ++totalMinted;
 
-        _mint(msg.sender, newItemId);
+        _mint(to, newItemId);
 
-        emit Events.Mint(msg.sender);
+        emit Events.Mint(to);
     }
 
     /// @notice Burn a token

src/test/ProtoGravaNFT.t.sol

@@ -124,6 +124,25 @@ contract ProtoGravNFTTestContract is ProtoGravaNFTTest {
         assertEq(protogravanft.balanceOf(address(this)), 1);
     }
 
+    /// @notice Test that airdrop can only be called by owner
+    function testAirdrop() public {
+        // Collect Alice balance of tokens before mint
+        uint256 alicePreBalance = alice.tokenBalance();
+        // Mint approved token
+        protogravanft.airdrop(alice.getAddress());
+        // Collect Alice balance of tokens after mint
+        uint256 alicePostBalance = alice.tokenBalance();
+        assertEq(alicePreBalance, 0);
+        assertEq(alicePostBalance, 1);
+        assertEq(protogravanft.totalSupply(), 1);
+        assertEq(protogravanft.ownerOf(1), alice.getAddress());
+        vm.expectRevert(abi.encodeWithSignature("OnePerUser()"));
+        alice.mint();
+        charlieAddress = charlie.getAddress();
+        vm.expectRevert(abi.encodeWithSignature("NotOwner()"));
+        alice.airdrop(charlieAddress);
+    }
+
     /// @notice Allow Alice to mint a token for approved hash
     function testAliceMint() public {
         // Collect Alice balance of tokens before mint

src/test/utils/ProtoGravaNFTUser.sol

@@ -39,6 +39,12 @@ contract ProtoGravaNFTUser is Test {
 
     /// ============ Inherited functionality ============
 
+    /// @notice Airdrop a token
+    /// @param to address receiving airdrop
+    function airdrop(address to) public {
+        return PROTOGRAVANFT.airdrop(to);
+    }
+
     /// @notice Mint a token
     function mint() public {
         return PROTOGRAVANFT.mint();