Complete comprehensive cache tests (#121)

* Add final cache limit tests
* Add in check for migration when 0 raw balance

contracts/masset/BasketManager.sol

@@ -533,9 +533,13 @@ contract BasketManager is
             uint256 cache = IERC20(bAsset).balanceOf(address(oldIntegration));
             // 2.1. Withdraw from the lending market
             uint256 lendingBal = oldIntegration.checkBalance(bAsset);
-            oldIntegration.withdraw(address(this), bAsset, lendingBal, false);
+            if(lendingBal > 0) {
+                oldIntegration.withdraw(address(this), bAsset, lendingBal, false);
+            }
             // 2.2. Withdraw from the cache, if any
-            oldIntegration.withdrawRaw(address(this), bAsset, cache);
+            if(cache > 0){
+                oldIntegration.withdrawRaw(address(this), bAsset, cache);
+            }
             uint256 total = lendingBal.add(cache);
 
             // 3. Update the integration address for this bAsset

contracts/masset/Masset.sol

@@ -290,7 +290,6 @@ contract Masset is
         // 2.2 - Else Deposit X if Cache > %
         else {
             // This check is in place to ensure that any token with a txFee is rejected
-            // Audit notes: Assumption made that if no fee is collected here then there is no txfee
             require(transferred == _quantity, "Asset not fully transferred");
 
             quantityDeposited = transferred;
@@ -356,14 +355,14 @@ contract Masset is
         Cache memory cache = _getCacheDetails();
 
         // 3. Deposit the input tokens
-        (uint256 amnountIn, ) =
+        (uint256 amountIn, ) =
             _depositTokens(args.input, inputDetails.bAsset.ratio, inputDetails.integrator, inputDetails.bAsset.isTransferFeeCharged, _quantity, cache.maxCache);
         // 3.1. Update the input balance
-        basketManager.increaseVaultBalance(inputDetails.index, inputDetails.integrator, amnountIn);
+        basketManager.increaseVaultBalance(inputDetails.index, inputDetails.integrator, amountIn);
 
         // 4. Validate the swap
         (bool swapValid, string memory swapValidityReason, uint256 swapOutput, bool applySwapFee) =
-            forgeValidator.validateSwap(cache.vaultBalanceSum, inputDetails.bAsset, outputDetails.bAsset, amnountIn);
+            forgeValidator.validateSwap(cache.vaultBalanceSum, inputDetails.bAsset, outputDetails.bAsset, amountIn);
         require(swapValid, swapValidityReason);
         require(swapOutput > 0, "Must withdraw something");
 

test-utils/machines/massetMachine.ts

@@ -591,6 +591,14 @@ export class MassetMachine {
         integratorBalBefore: number | BN,
         bAsset: Basset,
     ): Promise<ActionDetails> {
+        const hasTxFee = bAsset.isTransferFeeCharged;
+        if (hasTxFee) {
+            return {
+                expectInteraction: true,
+                amount,
+                rawBalance: new BN(0),
+            };
+        }
         const totalSupply = await mAsset.totalSupply();
         const surplus = await mAsset.surplus();
         const cacheSize = await mAsset.cacheSize();
@@ -609,7 +617,10 @@ export class MassetMachine {
                 type === "deposit"
                     ? newSum.sub(maxC.divn(2))
                     : BN.min(
-                          maxC.divn(2).add(amount).sub(new BN(integratorBalBefore)),
+                          maxC
+                              .divn(2)
+                              .add(amount)
+                              .sub(new BN(integratorBalBefore)),
                           new BN(bAsset.vaultBalance).sub(new BN(integratorBalBefore)),
                       ),
             rawBalance:

test-utils/math.ts

@@ -74,7 +74,7 @@ export const applyRatioMassetToBasset = (input: BN, ratio: BN | string): BN => {
 };
 
 // How many mAssets is this bAsset worth
-export const applyRatio = (bAssetQ: BN | string, ratio: BN | string): BN => {
+export const applyRatio = (bAssetQ: BN | string | number, ratio: BN | string): BN => {
     return new BN(bAssetQ).mul(new BN(ratio)).div(ratioScale);
 };
 

test/masset/TestBasketManager.spec.ts

@@ -775,13 +775,9 @@ contract("BasketManager", async (accounts) => {
         let newMigration: t.AaveV2IntegrationInstance;
         let maliciousIntegration: t.MaliciousAaveIntegrationInstance;
         let transferringAsset: t.MockERC20Instance;
-        before(async () => {
+        beforeEach(async () => {
             await createNewBasketManager();
             [, , transferringAsset] = integrationDetails.bAssets;
-            await transferringAsset.transfer(aaveIntegration.address, new BN(10000));
-            await aaveIntegration.deposit(transferringAsset.address, new BN(9000), false, {
-                from: governance,
-            });
             newMigration = await AaveIntegration.new();
             await newMigration.initialize(
                 nexus.address,
@@ -829,6 +825,10 @@ contract("BasketManager", async (accounts) => {
             );
         });
         it("should fail if the full amount is not transferred and deposited", async () => {
+            await transferringAsset.transfer(aaveIntegration.address, new BN(10000));
+            await aaveIntegration.deposit(transferringAsset.address, new BN(9000), false, {
+                from: governance,
+            });
             await expectRevert(
                 basketManager.migrateBassets(
                     [transferringAsset.address],
@@ -841,6 +841,10 @@ contract("BasketManager", async (accounts) => {
             );
         });
         it("should move all bAssets from a to b", async () => {
+            await transferringAsset.transfer(aaveIntegration.address, new BN(10000));
+            await aaveIntegration.deposit(transferringAsset.address, new BN(9000), false, {
+                from: governance,
+            });
             // get balances before
             const bal = await aaveIntegration.checkBalance.call(transferringAsset.address);
             expect(bal).bignumber.eq(new BN(9000));
@@ -875,6 +879,42 @@ contract("BasketManager", async (accounts) => {
                 newIntegrator: newMigration.address,
             });
         });
+        it("should pass if either rawBalance or balance are 0", async () => {
+            await transferringAsset.transfer(aaveIntegration.address, new BN(10000));
+            await aaveIntegration.deposit(transferringAsset.address, new BN(10000), false, {
+                from: governance,
+            });
+            // get balances before
+            const bal = await aaveIntegration.checkBalance.call(transferringAsset.address);
+            expect(bal).bignumber.eq(new BN(10000));
+            const rawBal = await transferringAsset.balanceOf(aaveIntegration.address);
+            expect(rawBal).bignumber.eq(new BN(0));
+            let integratorAddress = await basketManager.getBassetIntegrator(
+                transferringAsset.address,
+            );
+            expect(integratorAddress).eq(aaveIntegration.address);
+            // call migrate
+            const tx = await basketManager.migrateBassets(
+                [transferringAsset.address],
+                newMigration.address,
+                {
+                    from: sa.governor,
+                },
+            );
+            // moves all bAssets from old to new
+            const migratedBal = await newMigration.checkBalance.call(transferringAsset.address);
+            expect(migratedBal).bignumber.eq(bal);
+            const migratedRawBal = await transferringAsset.balanceOf(newMigration.address);
+            expect(migratedRawBal).bignumber.eq(rawBal);
+            // updates the integrator address
+            integratorAddress = await basketManager.getBassetIntegrator(transferringAsset.address);
+            expect(integratorAddress).eq(newMigration.address);
+            // emits BassetsMigrated
+            await expectEvent(tx.receipt, "BassetsMigrated", {
+                bAssets: [transferringAsset.address],
+                newIntegrator: newMigration.address,
+            });
+        });
     });
 
     describe("addBasset()", async () => {