Fix/drain expected (#312)

* updated WithdrawProxy.drain() to decrement expected

* added more tests and fixed division by 0 in processEpoch()

* Delete loanProofGenerator.js

* remove clones-with-immutable-args

* cleaned up tests

src/PublicVault.sol

@@ -335,7 +335,7 @@ contract PublicVault is VaultImplementation, IPublicVault, ERC4626Cloned {
     if ((address(currentWithdrawProxy) != address(0))) {
       uint256 proxySupply = currentWithdrawProxy.totalSupply();
 
-      s.liquidationWithdrawRatio = proxySupply.mulDivDown(1e18, totalSupply());
+      s.liquidationWithdrawRatio = totalSupply() == 0 ? 0 : proxySupply.mulDivDown(1e18, totalSupply());
 
       currentWithdrawProxy.setWithdrawRatio(s.liquidationWithdrawRatio);
       uint256 expected = currentWithdrawProxy.getExpected();
@@ -414,7 +414,7 @@ contract PublicVault is VaultImplementation, IPublicVault, ERC4626Cloned {
 
     address withdrawProxy = s.epochData[s.currentEpoch].withdrawProxy;
     if (
-      s.withdrawReserve > 0 &&
+      s.withdrawReserve > 0 && // only happens if previous withdrawProxy exists
       timeToEpochEnd() == 0 &&
       withdrawProxy != address(0)
     ) {

src/WithdrawProxy.sol

@@ -317,10 +317,14 @@ contract WithdrawProxy is ERC4626Cloned, WithdrawVaultBase {
     uint256 amount,
     address withdrawProxy
   ) public onlyVault returns (uint256) {
+    WPStorage storage s = _loadSlot();
+
     uint256 balance = ERC20(asset()).balanceOf(address(this));
     if (amount > balance) {
       amount = balance;
     }
+
+    s.expected -= amount;
     ERC20(asset()).safeTransfer(withdrawProxy, amount);
     return amount;
   }

src/test/TestHelpers.t.sol

@@ -424,7 +424,8 @@ contract TestHelpers is Deploy, ConsiderationTester {
     //warps to the first second after the epoch end
     assertTrue(
       block.timestamp <
-        PublicVault(vault).getEpochEnd(PublicVault(vault).getCurrentEpoch()) + 1
+        PublicVault(vault).getEpochEnd(PublicVault(vault).getCurrentEpoch()) + 1,
+      "warp failed"
     );
     vm.warp(
       PublicVault(vault).getEpochEnd(PublicVault(vault).getCurrentEpoch()) + 1