From 7d184d418cf39b6ba539ecae67879a5bfcf929d6 Mon Sep 17 00:00:00 2001
From: MantisClone <david.hunt-mateo@mantisdata.solutions>
Date: Tue, 5 Sep 2023 13:28:32 -0400
Subject: [PATCH] Add test to show fee transfer is skipped if amount is 0 and
 fee address is 0.

---
 .../test/contracts/ERC20FeeProxy.test.ts      | 45 +++++++++++++++++++
 1 file changed, 45 insertions(+)

diff --git a/packages/smart-contracts/test/contracts/ERC20FeeProxy.test.ts b/packages/smart-contracts/test/contracts/ERC20FeeProxy.test.ts
index 0b0b97d1c8..268c76c183 100644
--- a/packages/smart-contracts/test/contracts/ERC20FeeProxy.test.ts
+++ b/packages/smart-contracts/test/contracts/ERC20FeeProxy.test.ts
@@ -17,6 +17,7 @@ use(solidity);
 
 describe('contract: ERC20FeeProxy', () => {
   const feeAddress = '0xF4255c5e53a08f72b0573D1b8905C5a50aA9c2De';
+  const zeroFeeAddress = '0x0000000000000000000000000000000000000000';
   const referenceExample = '0xaaaa';
   let signer: Signer;
   let from: string;
@@ -199,6 +200,50 @@ describe('contract: ERC20FeeProxy', () => {
     expect(feeNewBalance.toString()).to.equals(feeOldBalance.toString());
   });
 
+  it('should skip fee transfer if fee amount is 0 and fee address is 0', async function () {
+    await testERC20.approve(erc20FeeProxy.address, '100');
+    const fromOldBalance = await testERC20.balanceOf(from);
+    const toOldBalance = await testERC20.balanceOf(to);
+    const feeOldBalance = await testERC20.balanceOf(zeroFeeAddress);
+
+    await expect(
+      erc20FeeProxy.transferFromWithReferenceAndFee(
+        testERC20.address,
+        to,
+        '100',
+        referenceExample,
+        '0',
+        zeroFeeAddress,
+        {
+          from,
+        },
+      ),
+    )
+      // transferReference indexes the event log, therefore the keccak256 is stored
+      .to.emit(erc20FeeProxy, 'TransferWithReferenceAndFee')
+      .withArgs(
+        testERC20.address,
+        to,
+        '100',
+        ethers.utils.keccak256(referenceExample),
+        '0',
+        zeroFeeAddress,
+      )
+      .and.to.emit(erc20FeeProxy, 'Transfer')
+      .withArgs(from, to, '100')
+      .and.to.not.emit(erc20FeeProxy, 'Transfer')
+      .withArgs(from, zeroFeeAddress, '0');
+
+    const fromNewBalance = await testERC20.balanceOf(from);
+    const toNewBalance = await testERC20.balanceOf(to);
+    const feeNewBalance = await testERC20.balanceOf(zeroFeeAddress);
+
+    // Check balance changes
+    expect(fromNewBalance.toString()).to.equals(fromOldBalance.sub(100).toString());
+    expect(toNewBalance.toString()).to.equals(toOldBalance.add(100).toString());
+    expect(feeNewBalance.toString()).to.equals(feeOldBalance.toString());
+  });
+
   it('transfers tokens for payment and fees on BadERC20', async function () {
     const badERC20Factory = new BadERC20__factory(signer);
     const badERC20 = await badERC20Factory.deploy(1000, 'BadERC20', 'BAD', 8);