AaveLeverageStrategy extension (#72)

* add AaveFLIStrategyExtension

* remove unused import

* set up basic constructor tests

* fix engage and update tests

* add rebalance and tests

* add iterateRebalance tests

* add ripcord tests

* add disengage tests

* add misc tests

* fix naming of flexibleLeverage utils functions

* fix how decimal units are handled

* add integration tests

* improve comments

* add aave v2 contracts

* clean up

* fix decimals

* update comments

* review changes

* fix comment

* update AaveLeverageModule and AaveV2 external contracts

* fix whitespace

Author: ncitron

contracts/adapters/AaveLeverageStrategyExtension.sol

@@ -28,7 +28,7 @@ import { ICErc20 } from "../interfaces/ICErc20.sol";
 import { IBaseManager } from "../interfaces/IBaseManager.sol";
 import { IChainlinkAggregatorV3 } from "../interfaces/IChainlinkAggregatorV3.sol";
 import { IComptroller } from "../interfaces/IComptroller.sol";
-import { ICompoundLeverageModule } from "../interfaces/ICompoundLeverageModule.sol";
+import { ILeverageModule } from "../interfaces/ILeverageModule.sol";
 import { ISetToken } from "../interfaces/ISetToken.sol";
 import { PreciseUnitMath } from "../lib/PreciseUnitMath.sol";
 import { StringArrayUtils } from "../lib/StringArrayUtils.sol";
@@ -104,7 +104,7 @@ contract FlexibleLeverageStrategyExtension is BaseExtension {
 
     struct ContractSettings {
         ISetToken setToken;                             // Instance of leverage token
-        ICompoundLeverageModule leverageModule;         // Instance of Compound leverage module
+        ILeverageModule leverageModule;                 // Instance of Compound leverage module
         IComptroller comptroller;                       // Instance of Compound Comptroller
         IChainlinkAggregatorV3 collateralPriceOracle;   // Chainlink oracle feed that returns prices in 8 decimals for collateral asset
         IChainlinkAggregatorV3 borrowPriceOracle;       // Chainlink oracle feed that returns prices in 8 decimals for borrow asset

contracts/adapters/FlexibleLeverageStrategyExtension.sol

@@ -3,7 +3,7 @@ pragma experimental "ABIEncoderV2";
 
 import { ISetToken } from "./ISetToken.sol";
 
-interface ICompoundLeverageModule {
+interface ILeverageModule {
     function sync(
         ISetToken _setToken
     ) external;

contracts/interfaces/ICompoundLeverageModule.sol renamed to contracts/interfaces/ILeverageModule.sol

@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: agpl-3.0
+pragma solidity 0.6.10;
+pragma experimental ABIEncoderV2;
+
+interface IProtocolDataProvider {
+  struct TokenData {
+    string symbol;
+    address tokenAddress;
+  }
+
+  function ADDRESSES_PROVIDER() external view returns (address);
+  function getAllReservesTokens() external view returns (TokenData[] memory);
+  function getAllATokens() external view returns (TokenData[] memory);
+  function getReserveConfigurationData(address asset) external view returns (uint256 decimals, uint256 ltv, uint256 liquidationThreshold, uint256 liquidationBonus, uint256 reserveFactor, bool usageAsCollateralEnabled, bool borrowingEnabled, bool stableBorrowRateEnabled, bool isActive, bool isFrozen);
+  function getReserveData(address asset) external view returns (uint256 availableLiquidity, uint256 totalStableDebt, uint256 totalVariableDebt, uint256 liquidityRate, uint256 variableBorrowRate, uint256 stableBorrowRate, uint256 averageStableBorrowRate, uint256 liquidityIndex, uint256 variableBorrowIndex, uint40 lastUpdateTimestamp);
+  function getUserReserveData(address asset, address user) external view returns (uint256 currentATokenBalance, uint256 currentStableDebt, uint256 currentVariableDebt, uint256 principalStableDebt, uint256 scaledVariableDebt, uint256 stableBorrowRate, uint256 liquidityRate, uint40 stableRateLastUpdated, bool usageAsCollateralEnabled);
+  function getReserveTokensAddresses(address asset) external view returns (address aTokenAddress, address stableDebtTokenAddress, address variableDebtTokenAddress);
+}