Initial commit: add .gitignore and README

test/Uniswap.test.sol

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+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.20;
+
+import "forge-std/Test.sol";
+import "../contracts/examples/UniswapV3Swap.sol";
+import "../contracts/interfaces/IERC20.sol";
+
+contract UniswapTest is Test {
+    UniswapV3Swap public uniswapSwap;
+    
+    // Mainnet addresses
+    address constant SWAP_ROUTER = 0x68b3465833fb72A70ecDF485E0e4C7bD8665Fc45;
+    address constant USDC = 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48;
+    address constant WETH = 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2;
+    
+    uint256 mainnetFork;
+
+    function setUp() public {
+        // Fork mainnet
+        mainnetFork = vm.createFork(vm.envString("MAINNET_RPC_URL"));
+        vm.selectFork(mainnetFork);
+
+        // Deploy contract
+        uniswapSwap = new UniswapV3Swap(SWAP_ROUTER);
+    }
+
+    function testSwapExactInputSingle() public {
+        // Setup: Get some USDC from a whale
+        address whale = 0x47ac0Fb4F2D84898e4D9E7b4DaB3C24507a6D503; // USDC whale
+        uint256 amountIn = 1000 * 10**6; // 1000 USDC
+        uint24 fee = 3000; // 0.3% fee tier
+        uint256 deadline = block.timestamp + 600; // 10 minutes
+
+        // Impersonate whale and transfer USDC to test contract
+        vm.startPrank(whale);
+        IERC20(USDC).transfer(address(this), amountIn);
+        vm.stopPrank();
+
+        // Record initial WETH balance
+        uint256 initialWETH = IERC20(WETH).balanceOf(address(this));
+
+        // Approve and swap
+        IERC20(USDC).approve(address(uniswapSwap), amountIn);
+        uint256 amountOut = uniswapSwap.swapExactInputSingle(
+            USDC,
+            WETH,
+            fee,
+            amountIn,
+            0, // No slippage protection for test
+            deadline
+        );
+
+        // Check that we received WETH
+        uint256 finalWETH = IERC20(WETH).balanceOf(address(this));
+        assertGt(finalWETH, initialWETH, "Should have received WETH");
+        assertGt(amountOut, 0, "Should have output amount");
+    }
+}
+