Add Balancer weighted pool oracle deployment script (#17)

* Add balancer price oracle

* Add Balancer weighted pool oracle deployment script

script/DeployAllContracts.s.sol

@@ -5,14 +5,33 @@ import {Script} from "forge-std/Script.sol";
 
 import {DeployUniswapV2PriceOracle, UniswapV2PriceOracle} from "./single-deployment/UniswapV2PriceOracle.s.sol";
 import {DeployConstantProduct, ConstantProduct} from "./single-deployment/ConstantProduct.s.sol";
+import {
+    DeployBalancerWeightedPoolPriceOracle,
+    BalancerWeightedPoolPriceOracle
+} from "./single-deployment/BalancerWeightedPoolPriceOracle.s.sol";
 
-contract DeployAllContracts is DeployConstantProduct, DeployUniswapV2PriceOracle {
-    function run() public override(DeployConstantProduct, DeployUniswapV2PriceOracle) {
+contract DeployAllContracts is
+    DeployConstantProduct,
+    DeployUniswapV2PriceOracle,
+    DeployBalancerWeightedPoolPriceOracle
+{
+    function run()
+        public
+        override(DeployConstantProduct, DeployUniswapV2PriceOracle, DeployBalancerWeightedPoolPriceOracle)
+    {
         deployAll();
     }
 
-    function deployAll() public returns (ConstantProduct constantProduct, UniswapV2PriceOracle uniswapV2PriceOracle) {
+    function deployAll()
+        public
+        returns (
+            ConstantProduct constantProduct,
+            UniswapV2PriceOracle uniswapV2PriceOracle,
+            BalancerWeightedPoolPriceOracle balancerWeightedPoolPriceOracle
+        )
+    {
         constantProduct = deployConstantProduct();
         uniswapV2PriceOracle = deployUniswapV2PriceOracle();
+        balancerWeightedPoolPriceOracle = deployBalancerWeightedPoolPriceOracle();
     }
 }

script/single-deployment/BalancerWeightedPoolPriceOracle.s.sol

@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: GPL-3.0
+pragma solidity >=0.8.0 <0.9.0;
+
+import {Script, console} from "forge-std/Script.sol";
+
+import {BalancerWeightedPoolPriceOracle, IVault} from "src/oracles/BalancerWeightedPoolPriceOracle.sol";
+
+contract DeployBalancerWeightedPoolPriceOracle is Script {
+    string constant balancerVaultEnv = "BALANCER_VAULT";
+    IVault internal vault;
+
+    constructor() {
+        try vm.envAddress(balancerVaultEnv) returns (address vault_) {
+            vault = IVault(vault_);
+        } catch {
+            vault = defaultBalancerVault();
+        }
+        console.log("Balancer vault at %s.", address(vault));
+        // We assume that if there's code at that address, then it's a Balancer
+        // vault deployment. This isn't guaranteed because they don't use
+        // deterministic addresses and in theory there could be any contract
+        // there.
+        require(address(vault).code.length > 0, "no code at expected Balancer vault");
+    }
+
+    function run() public virtual {
+        deployBalancerWeightedPoolPriceOracle();
+    }
+
+    function deployBalancerWeightedPoolPriceOracle() internal returns (BalancerWeightedPoolPriceOracle) {
+        vm.broadcast();
+        return new BalancerWeightedPoolPriceOracle(vault);
+    }
+
+    function defaultBalancerVault() internal pure returns (IVault) {
+        // Balancer uses the same address on each supported chain until now:
+        // https://docs.balancer.fi/reference/contracts/deployment-addresses/mainnet.html
+        // Chains: Arbitrum, Avalanche, Base, Gnosis, Goerli, Mainnet, Optimism,
+        // Polygon, Sepolia, Zkevm
+        return IVault(0xBA12222222228d8Ba445958a75a0704d566BF2C8);
+    }
+}

test/script/DeployAllContracts.t.sol

@@ -3,12 +3,15 @@ pragma solidity >=0.8.0 <0.9.0;
 
 import {Test} from "forge-std/Test.sol";
 
+import {BalancerSetUp} from "./single-deployment/balancer/BalancerSetUp.sol";
+
 import {DeployAllContracts} from "script/DeployAllContracts.s.sol";
 
-contract DeployAllContractsTest is Test {
+contract DeployAllContractsTest is Test, BalancerSetUp {
     DeployAllContracts script;
 
     function setUp() public {
+        setUpBalancerVault();
         script = new DeployAllContracts();
     }
 

test/script/single-deployment/DeployBalancerWeightedPoolPriceOracle.t.sol

@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: GPL-3.0
+pragma solidity >=0.8.0 <0.9.0;
+
+import {Test} from "forge-std/Test.sol";
+
+import {BalancerSetUp} from "./balancer/BalancerSetUp.sol";
+
+import {DeployBalancerWeightedPoolPriceOracle} from "script/single-deployment/BalancerWeightedPoolPriceOracle.s.sol";
+
+contract DeployBalancerWeightedPoolPriceOracleTest is Test, BalancerSetUp {
+    DeployBalancerWeightedPoolPriceOracle script;
+
+    function setUp() public {
+        setUpBalancerVault();
+        script = new DeployBalancerWeightedPoolPriceOracle();
+    }
+
+    function testDoesNotRevert() public {
+        script.run();
+    }
+}

test/script/single-deployment/balancer/BalancerSetUp.sol

@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: GPL-3.0
+pragma solidity >=0.8.0 <0.9.0;
+
+import {Test} from "forge-std/Test.sol";
+
+abstract contract BalancerSetUp is Test {
+    function setUpBalancerVault() internal {
+        vm.etch(0xBA12222222228d8Ba445958a75a0704d566BF2C8, hex"1337");
+    }
+}