Fix/missing constant sum controller

src/ConstantSum/ConstantSum.sol

@@ -63,6 +63,7 @@ contract ConstantSum is PairStrategy {
 
         internalParams[poolId].price = params.price;
         internalParams[poolId].swapFee = params.swapFee;
+        internalParams[poolId].controller = params.controller;
 
         // Get the trading function and check this is valid
         invariant =
@@ -105,6 +106,7 @@ contract ConstantSum is PairStrategy {
 
         params.price = internalParams[poolId].price;
         params.swapFee = internalParams[poolId].swapFee;
+        params.controller = internalParams[poolId].controller;
 
         return abi.encode(params);
     }

test/ConstantSum/unit/GetPoolParams.t.sol

@@ -1,6 +1,43 @@
 // SPDX-License-Identifier: UNLICENSED
 pragma solidity ^0.8.13;
 
-import { ConstantSumSetUp } from "./SetUp.sol";
+import { ConstantSumSetUp, ConstantSumParams, InitParams } from "./SetUp.sol";
 
-contract ConstantSumGetPoolParamsTest is ConstantSumSetUp { }
+contract ConstantSumGetPoolParamsTest is ConstantSumSetUp {
+    function test_ConstantSum_getPoolParams() public {
+        ConstantSumParams memory initialParams = ConstantSumParams({
+            price: 1 ether,
+            swapFee: TEST_SWAP_FEE,
+            controller: address(this)
+        });
+
+        uint256 reserveX = 1 ether;
+        uint256 reserveY = 1 ether;
+
+        bytes memory initData =
+            solver.getInitialPoolData(reserveX, reserveY, initialParams);
+
+        address[] memory tokens = new address[](2);
+        tokens[0] = address(tokenX);
+        tokens[1] = address(tokenY);
+
+        InitParams memory initParams = InitParams({
+            name: "",
+            symbol: "",
+            strategy: address(constantSum),
+            tokens: tokens,
+            data: initData,
+            feeCollector: address(0),
+            controllerFee: 0
+        });
+
+        (uint256 poolId,,) = dfmm.init(initParams);
+
+        ConstantSumParams memory poolParams =
+            abi.decode(constantSum.getPoolParams(poolId), (ConstantSumParams));
+
+        assertEq(poolParams.price, initialParams.price);
+        assertEq(poolParams.swapFee, initialParams.swapFee);
+        assertEq(poolParams.controller, initialParams.controller);
+    }
+}