better abstraction for invariants

.gitignore

@@ -14,3 +14,5 @@ deployments/hardhat
 deployments/docker
 subgraph/generated
 subgraph/tests/.bin/*
+crytic-export/
+corpus/

contracts/echidna/Addresses.sol

@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity =0.8.10;
+
+import "../Vault.sol";
+import "../test/TestERC20.sol";
+
+contract Addresses {
+    Vault vault = Vault(0x6A4A62E5A7eD13c361b176A5F62C2eE620Ac0DF8);
+    TestERC20 underlying = TestERC20(0x1dC4c1cEFEF38a777b15aA20260a54E584b16C48);
+}

contracts/echidna/Echidna_Deposit_Withdraw.sol

@@ -0,0 +1,19 @@
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity =0.8.10;
+import "./Helper.sol";
+
+contract Echidna_Deposit_Withdraw is Helper {
+
+    // zero address should always revert
+    function withdraw_zero_address_recipient(uint256[] memory _ids) public {
+        withdraw_should_revert(address(0), _ids);
+    }
+
+    function withdraw_should_revert(address recipient, uint256[] memory _ids) internal {
+        try vault.withdraw(recipient, _ids) {
+            assert(false);
+        } catch {
+            assert(true);
+        }
+    }
+}

contracts/echidna/Echidna_Deposit_Withdraw.yml

@@ -0,0 +1,5 @@
+initialize: contracts/echidna/init.json
+coverage: true
+testMode: assertion
+corpusDir: 'corpus'
+codeSize: 0xfffffffffff

contracts/echidna/Helper.sol

@@ -0,0 +1,8 @@
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity =0.8.10;
+import "./Addresses.sol";
+
+contract Helper is Addresses {
+
+
+}