Add test infrastructure

foundry.toml

@@ -6,6 +6,8 @@ libs = ["lib"]
 remappings = [
   "lib/composable-cow:cowprotocol/=lib/composable-cow/lib/cowprotocol/src/contracts/",
   "lib/composable-cow:safe/=lib/composable-cow/lib/safe/contracts/",
+  "lib/composable-cow:@openzeppelin/=lib/composable-cow/lib/@openzeppelin/contracts/",
+  "lib/composable-cow:@openzeppelin/contracts/=lib/composable-cow/lib/@openzeppelin/contracts/",
 ]
 
 # See more config options https://github.com/foundry-rs/foundry/blob/master/crates/config/README.md#all-options

test/ConstantProduct.t.sol

@@ -1,7 +1,19 @@
 // SPDX-License-Identifier: UNLICENSED
 pragma solidity ^0.8.13;
 
-import {Test} from "forge-std/Test.sol";
+import {IERC20} from "lib/composable-cow/lib/@openzeppelin/contracts/interfaces/IERC20.sol";
+import {BaseComposableCoWTest} from "lib/composable-cow/test/ComposableCoW.base.t.sol";
+
 import {ConstantProduct} from "../src/ConstantProduct.sol";
 
-contract CounterTest is Test {}
+contract E2eCounterTest is BaseComposableCoWTest {
+    ConstantProduct constantProduct;
+    address safe;
+
+    function setUp() public virtual override(BaseComposableCoWTest) {
+        super.setUp();
+
+        constantProduct = new ConstantProduct();
+    }
+}
+