Add test for preventing delegation to address(0) (#89)

* Add dotenv

* Add test for changing delegation to address 0

* Comment nit

hardhat.config.test.ts

@@ -1,6 +1,7 @@
 import "@nomiclabs/hardhat-waffle";
 import "hardhat-gas-reporter";
 import "solidity-coverage";
+import "dotenv/config";
 
 import { HardhatUserConfig } from "hardhat/config";
 

package.json

@@ -51,6 +51,7 @@
     "chai-almost": "^1.0.1",
     "coveralls": "^3.1.0",
     "cspell": "^5.4.1",
+    "dotenv": "^16.4.5",
     "eslint": "^7.27.0",
     "eslint-config-prettier": "^8.3.0",
     "ethereum-waffle": "^3.3.0",

test/lockingVault.ts

@@ -196,6 +196,15 @@ describe("Locking Vault", function () {
     expect(votingPower).to.be.eq(one.mul(3));
   });
 
+  it("Does not allow changing delegates to zero address", async () => {
+    // User 0 deposits and delegates to themselves
+    await vault.deposit(signers[0].address, one, signers[0].address);
+    // User 0 tries to change the delegation to zero address
+    await expect(vault.changeDelegation(zeroAddress)).to.be.revertedWith(
+      "Zero addr delegation"
+    );
+  });
+
   it("Withdraws properly", async () => {
     // First we setup the user and give accounts some voting power
     await vault.deposit(signers[0].address, one, signers[2].address);