Foundry init.

foundry.toml

@@ -0,0 +1,6 @@
+[profile.default]
+src = "src"
+out = "out"
+libs = ["lib"]
+
+# See more config options https://github.com/foundry-rs/foundry/blob/master/crates/config/README.md#all-options

script/Counter.s.sol

@@ -0,0 +1,19 @@
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity ^0.8.13;
+
+import {Script, console} from "forge-std/Script.sol";
+import {Counter} from "../src/Counter.sol";
+
+contract CounterScript is Script {
+    Counter public counter;
+
+    function setUp() public {}
+
+    function run() public {
+        vm.startBroadcast();
+
+        counter = new Counter();
+
+        vm.stopBroadcast();
+    }
+}

src/Counter.sol

@@ -0,0 +1,14 @@
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity ^0.8.13;
+
+contract Counter {
+    uint256 public number;
+
+    function setNumber(uint256 newNumber) public {
+        number = newNumber;
+    }
+
+    function increment() public {
+        number++;
+    }
+}

test/Counter.t.sol

@@ -0,0 +1,24 @@
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity ^0.8.13;
+
+import {Test, console} from "forge-std/Test.sol";
+import {Counter} from "../src/Counter.sol";
+
+contract CounterTest is Test {
+    Counter public counter;
+
+    function setUp() public {
+        counter = new Counter();
+        counter.setNumber(0);
+    }
+
+    function test_Increment() public {
+        counter.increment();
+        assertEq(counter.number(), 1);
+    }
+
+    function testFuzz_SetNumber(uint256 x) public {
+        counter.setNumber(x);
+        assertEq(counter.number(), x);
+    }
+}