test: integration tests for TokenFactory deploy flow

Author: MilosMicun

src/Token.sol

@@ -7,13 +7,19 @@ error ZeroAddress();
 contract Token {
     mapping(address => uint256) public balanceOf;
     uint256 public totalSupply;
+    string public name;
+    string public symbol;
+    uint8 public constant decimals = 18;
 
     event Transfer(address indexed from, address indexed to, uint256 amount);
 
-    constructor(uint256 initialSupply) {
-        balanceOf[msg.sender] = initialSupply;
+    constructor(address owner, string memory _name, string memory _symbol, uint256 initialSupply) {
+        if (owner == address(0)) revert ZeroAddress();
+        name = _name;
+        symbol = _symbol;
+        balanceOf[owner] = initialSupply;
         totalSupply = initialSupply;
-        emit Transfer(address(0), msg.sender, initialSupply);
+        emit Transfer(address(0), owner, initialSupply);
     }
 
     function transfer(address to, uint256 amount) external returns (bool) {

src/TokenFactory.sol

@@ -1,4 +1,21 @@
 // SPDX-License-Identifier: MIT
 pragma solidity ^0.8.20;
 
-contract TokenFactory {}
+import {Token} from "./Token.sol";
+
+contract TokenFactory {
+    address[] public tokens;
+
+    event TokenDeployed(address indexed token, address indexed owner, string name, string symbol);
+
+    function deployToken(string memory _name, string memory _symbol, uint256 initialSupply) external returns (address) {
+        Token token = new Token(msg.sender, _name, _symbol, initialSupply);
+        tokens.push(address(token));
+        emit TokenDeployed(address(token), msg.sender, _name, _symbol);
+        return address(token);
+    }
+
+    function tokensLength() external view returns (uint256) {
+        return tokens.length;
+    }
+}

test/Integration/TokenFactory.t.sol

@@ -0,0 +1,58 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.20;
+
+import "forge-std/Test.sol";
+import {TokenFactory} from "../../src/TokenFactory.sol";
+import {Token} from "../../src/Token.sol";
+
+contract TokenFactoryIntegrationTest is Test {
+    TokenFactory factory;
+    address alice = makeAddr("alice");
+    address bob = makeAddr("bob");
+    address carol = makeAddr("carol");
+
+    function setUp() public {
+        factory = new TokenFactory();
+    }
+
+    function testFactoryDeployToken() public {
+        vm.prank(alice);
+        address tokenA = factory.deployToken("TokenA", "TKA", 1000);
+        Token token = Token(tokenA);
+        assertEq(factory.tokensLength(), 1);
+        assertEq(factory.tokens(0), tokenA);
+        assertTrue(tokenA.code.length > 0);
+        assertEq(token.name(), "TokenA");
+        assertEq(token.symbol(), "TKA");
+        assertEq(token.balanceOf(alice), 1000);
+        assertEq(token.totalSupply(), 1000);
+    }
+
+    function testFactoryDeploysUniqueTokenAddresses() public {
+        vm.prank(alice);
+        address tokenA = factory.deployToken("TokenA", "TKA", 1000);
+        vm.prank(bob);
+        address tokenB = factory.deployToken("TokenB", "TKB", 1000);
+        assertEq(factory.tokensLength(), 2);
+        assertEq(factory.tokens(0), tokenA);
+        assertEq(factory.tokens(1), tokenB);
+        assertTrue(tokenA != tokenB);
+    }
+
+    function testDeployedTokensKeepIndependentState() public {
+        vm.prank(alice);
+        address tokenA = factory.deployToken("TokenA", "TKA", 1000);
+        vm.prank(bob);
+        address tokenB = factory.deployToken("TokenB", "TKB", 2000);
+        Token token1 = Token(tokenA);
+        Token token2 = Token(tokenB);
+        assertEq(token1.name(), "TokenA");
+        assertEq(token2.name(), "TokenB");
+        assertEq(token1.symbol(), "TKA");
+        assertEq(token2.symbol(), "TKB");
+        assertEq(token1.balanceOf(alice), 1000);
+        assertEq(token2.balanceOf(bob), 2000);
+        assertEq(token1.totalSupply(), 1000);
+        assertEq(token2.totalSupply(), 2000);
+    }
+}

test/Unit/Token.t.sol

@@ -8,7 +8,7 @@ contract TokenTest is Test {
     Token token;
 
     function setUp() public {
-        token = new Token(1000);
+        token = new Token(address(this), "TestToken", "TT", 1000);
     }
 
     function testTransferSuccess() public {