diff --git a/src/swappers/TradeFactorySwapper.sol b/src/swappers/TradeFactorySwapper.sol
index 77cfcb9..ae794f9 100644
--- a/src/swappers/TradeFactorySwapper.sol
+++ b/src/swappers/TradeFactorySwapper.sol
@@ -28,7 +28,7 @@ abstract contract TradeFactorySwapper {
      *   proper functions to avoid issues.
      * @return The current trade factory in use if any.
      */
-    function tradeFactory() public view returns (address) {
+    function tradeFactory() public view virtual returns (address) {
         return _tradeFactory;
     }
 
@@ -38,14 +38,17 @@ abstract contract TradeFactorySwapper {
      *   proper functions to avoid issues.
      * @return The current array of tokens being sold if any.
      */
-    function rewardTokens() public view returns (address[] memory) {
+    function rewardTokens() public view virtual returns (address[] memory) {
         return _rewardTokens;
     }
 
     /**
      * @dev Add an array of tokens to sell to its corresponding `_to_.
      */
-    function _addTokens(address[] memory _from, address[] memory _to) internal {
+    function _addTokens(
+        address[] memory _from,
+        address[] memory _to
+    ) internal virtual {
         for (uint256 i; i < _from.length; ++i) {
             _addToken(_from[i], _to[i]);
         }
@@ -54,7 +57,7 @@ abstract contract TradeFactorySwapper {
     /**
      * @dev Add the `_tokenFrom` to be sold to `_tokenTo` through the Trade Factory
      */
-    function _addToken(address _tokenFrom, address _tokenTo) internal {
+    function _addToken(address _tokenFrom, address _tokenTo) internal virtual {
         address _tf = tradeFactory();
         if (_tf != address(0)) {
             ERC20(_tokenFrom).forceApprove(_tf, type(uint256).max);
@@ -68,7 +71,10 @@ abstract contract TradeFactorySwapper {
      * @dev Remove a specific `_tokenFrom` that was previously added to not be
      * sold through the Trade Factory any more.
      */
-    function _removeToken(address _tokenFrom, address _tokenTo) internal {
+    function _removeToken(
+        address _tokenFrom,
+        address _tokenTo
+    ) internal virtual {
         address _tf = tradeFactory();
         address[] memory _rewardTokensLocal = rewardTokens();
         for (uint256 i; i < _rewardTokensLocal.length; ++i) {
@@ -95,7 +101,7 @@ abstract contract TradeFactorySwapper {
     /**
      * @dev Removes all reward tokens and delete the Trade Factory.
      */
-    function _deleteRewardTokens() internal {
+    function _deleteRewardTokens() internal virtual {
         _removeTradeFactoryPermissions();
         delete _rewardTokens;
     }
@@ -109,7 +115,7 @@ abstract contract TradeFactorySwapper {
     function _setTradeFactory(
         address tradeFactory_,
         address _tokenTo
-    ) internal {
+    ) internal virtual {
         address _tf = tradeFactory();
 
         // Remove any old Trade Factory
@@ -136,7 +142,7 @@ abstract contract TradeFactorySwapper {
     /**
      * @dev Remove any active approvals and set the trade factory to address(0).
      */
-    function _removeTradeFactoryPermissions() internal {
+    function _removeTradeFactoryPermissions() internal virtual {
         address _tf = tradeFactory();
         address[] memory rewardTokensLocal = rewardTokens();
         for (uint256 i; i < rewardTokensLocal.length; ++i) {
@@ -149,7 +155,7 @@ abstract contract TradeFactorySwapper {
     /**
      * @notice Used for TradeFactory to claim rewards.
      */
-    function claimRewards() external {
+    function claimRewards() external virtual {
         require(msg.sender == _tradeFactory, "!authorized");
         _claimRewards();
     }
diff --git a/src/test/Auction.t.sol b/src/test/Auction.t.sol
index dce5279..826426e 100644
--- a/src/test/Auction.t.sol
+++ b/src/test/Auction.t.sol
@@ -295,6 +295,7 @@ contract AuctionTest is Setup, ITaker {
         skip(auction.auctionLength() / 2);
 
         uint256 needed = auction.getAmountNeeded(id, _amount);
+        uint256 beforeAsset = ERC20(asset).balanceOf(address(this));
 
         airdrop(ERC20(asset), address(this), needed);
 
@@ -311,7 +312,7 @@ contract AuctionTest is Setup, ITaker {
         (, , , _available) = auction.auctionInfo(id);
         assertEq(_available, 0);
 
-        assertEq(ERC20(asset).balanceOf(address(this)), 0);
+        assertEq(ERC20(asset).balanceOf(address(this)), beforeAsset);
         assertEq(ERC20(from).balanceOf(address(this)), before + _amount);
         assertEq(ERC20(from).balanceOf(address(auction)), 0);
         assertEq(ERC20(asset).balanceOf(address(mockStrategy)), needed);
@@ -351,6 +352,7 @@ contract AuctionTest is Setup, ITaker {
         uint256 toTake = (_amount * _percent) / MAX_BPS;
         uint256 left = _amount - toTake;
         uint256 needed = auction.getAmountNeeded(id, toTake);
+        uint256 beforeAsset = ERC20(asset).balanceOf(address(this));
 
         airdrop(ERC20(asset), address(this), needed);
 
@@ -366,7 +368,7 @@ contract AuctionTest is Setup, ITaker {
 
         (, , , _available) = auction.auctionInfo(id);
         assertEq(_available, left);
-        assertEq(ERC20(asset).balanceOf(address(this)), 0);
+        assertEq(ERC20(asset).balanceOf(address(this)), beforeAsset);
         assertEq(ERC20(from).balanceOf(address(this)), before + toTake);
         assertEq(ERC20(from).balanceOf(address(auction)), left);
         assertEq(ERC20(asset).balanceOf(address(mockStrategy)), needed);
@@ -405,6 +407,7 @@ contract AuctionTest is Setup, ITaker {
         uint256 toTake = _amount / 2;
         uint256 left = _amount - toTake;
         uint256 needed = auction.getAmountNeeded(id, toTake);
+        uint256 beforeAsset = ERC20(asset).balanceOf(address(this));
 
         airdrop(ERC20(asset), address(this), needed);
 
@@ -424,7 +427,7 @@ contract AuctionTest is Setup, ITaker {
 
         (, , , _available) = auction.auctionInfo(id);
         assertEq(_available, left);
-        assertEq(ERC20(asset).balanceOf(address(this)), 0);
+        assertEq(ERC20(asset).balanceOf(address(this)), beforeAsset);
         assertEq(ERC20(from).balanceOf(address(this)), before + toTake);
         assertEq(ERC20(from).balanceOf(address(auction)), left);
         assertEq(ERC20(asset).balanceOf(address(mockStrategy)), needed);
diff --git a/src/test/AuctionSwapper.t.sol b/src/test/AuctionSwapper.t.sol
index d8fb5bd..cc6be41 100644
--- a/src/test/AuctionSwapper.t.sol
+++ b/src/test/AuctionSwapper.t.sol
@@ -309,6 +309,7 @@ contract AuctionSwapperTest is Setup {
         uint256 toTake = (_amount * _percent) / MAX_BPS;
         uint256 left = _amount - toTake;
         uint256 needed = auction.getAmountNeeded(id, toTake);
+        uint256 beforeAsset = ERC20(asset).balanceOf(address(this));
 
         airdrop(ERC20(asset), address(this), needed);
 
@@ -324,7 +325,7 @@ contract AuctionSwapperTest is Setup {
 
         (, , , _available) = auction.auctionInfo(id);
         assertEq(_available, left);
-        assertEq(ERC20(asset).balanceOf(address(this)), 0);
+        assertEq(ERC20(asset).balanceOf(address(this)), beforeAsset);
         assertEq(ERC20(from).balanceOf(address(this)), before + toTake);
         assertEq(ERC20(from).balanceOf(address(auction)), left);
         assertEq(ERC20(asset).balanceOf(address(swapper)), needed);
@@ -470,6 +471,7 @@ contract AuctionSwapperTest is Setup {
         uint256 toTake = (kickable * _percent) / MAX_BPS;
         uint256 left = kickable - toTake;
         uint256 needed = auction.getAmountNeeded(id, toTake);
+        uint256 beforeAsset = ERC20(asset).balanceOf(address(this));
 
         airdrop(ERC20(asset), address(this), needed);
 
@@ -487,7 +489,7 @@ contract AuctionSwapperTest is Setup {
 
         (, , , _available) = auction.auctionInfo(id);
         assertEq(_available, left);
-        assertEq(ERC20(asset).balanceOf(address(this)), 0);
+        assertEq(ERC20(asset).balanceOf(address(this)), beforeAsset);
         assertEq(ERC20(from).balanceOf(address(this)), before + toTake);
         assertEq(ERC20(from).balanceOf(address(auction)), left);
         assertEq(ERC20(asset).balanceOf(address(swapper)), needed);
diff --git a/src/test/BaseAuctioneer.t.sol b/src/test/BaseAuctioneer.t.sol
index c689418..ea9df23 100644
--- a/src/test/BaseAuctioneer.t.sol
+++ b/src/test/BaseAuctioneer.t.sol
@@ -276,6 +276,7 @@ contract BaseAuctioneerTest is Setup {
         uint256 toTake = (_amount * _percent) / MAX_BPS;
         uint256 left = _amount - toTake;
         uint256 needed = auctioneer.getAmountNeeded(id, toTake);
+        uint256 beforeAsset = ERC20(asset).balanceOf(address(this));
 
         airdrop(ERC20(asset), address(this), needed);
 
@@ -291,7 +292,7 @@ contract BaseAuctioneerTest is Setup {
 
         (, , , _available) = auctioneer.auctionInfo(id);
         assertEq(_available, left);
-        assertEq(ERC20(asset).balanceOf(address(this)), 0);
+        assertEq(ERC20(asset).balanceOf(address(this)), beforeAsset);
         assertEq(ERC20(from).balanceOf(address(this)), before + toTake);
         assertEq(ERC20(from).balanceOf(address(auctioneer)), left);
         assertEq(ERC20(asset).balanceOf(address(auctioneer)), needed);
@@ -430,6 +431,7 @@ contract BaseAuctioneerTest is Setup {
         uint256 toTake = (kickable * _percent) / MAX_BPS;
         uint256 left = _amount - toTake;
         uint256 needed = auctioneer.getAmountNeeded(id, toTake);
+        uint256 beforeAsset = ERC20(asset).balanceOf(address(this));
 
         airdrop(ERC20(asset), address(this), needed);
 
@@ -447,7 +449,7 @@ contract BaseAuctioneerTest is Setup {
 
         (, , , _available) = auctioneer.auctionInfo(id);
         assertEq(_available, kickable - toTake);
-        assertEq(ERC20(asset).balanceOf(address(this)), 0);
+        assertEq(ERC20(asset).balanceOf(address(this)), beforeAsset);
         assertEq(ERC20(from).balanceOf(address(this)), before + toTake);
         assertEq(ERC20(from).balanceOf(address(auctioneer)), left);
         assertEq(ERC20(asset).balanceOf(address(auctioneer)), needed);