Magic Numbers Fixed (#41)

Cyfrin · Sep 11, 2023 · ac725e2 · ac725e2
1 parent 55e15db
commit ac725e2
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Showing 2 changed files with 14 additions and 3 deletions.
diff --git a/src/DSCEngine.sol b/src/DSCEngine.sol
@@ -70,6 +70,7 @@ contract DSCEngine is ReentrancyGuard {
 
     uint256 private constant LIQUIDATION_THRESHOLD = 50; // This means you need to be 200% over-collateralized
     uint256 private constant LIQUIDATION_BONUS = 10; // This means you get assets at a 10% discount when liquidating
+    uint256 private constant LIQUIDATION_PRECISION = 100;
     uint256 private constant MIN_HEALTH_FACTOR = 1e18;
     uint256 private constant PRECISION = 1e18;
     uint256 private constant ADDITIONAL_FEED_PRECISION = 1e10;
@@ -209,7 +210,7 @@ contract DSCEngine is ReentrancyGuard {
         // So we are giving the liquidator $110 of WETH for 100 DSC
         // We should implement a feature to liquidate in the event the protocol is insolvent
         // And sweep extra amounts into a treasury
-        uint256 bonusCollateral = (tokenAmountFromDebtCovered * LIQUIDATION_BONUS) / 100;
+        uint256 bonusCollateral = (tokenAmountFromDebtCovered * LIQUIDATION_BONUS) / LIQUIDATION_PRECISION;
         // Burn DSC equal to debtToCover
         // Figure out how much collateral to recover based on how much burnt
         _redeemCollateral(collateral, tokenAmountFromDebtCovered + bonusCollateral, user, msg.sender);
@@ -317,8 +318,8 @@ contract DSCEngine is ReentrancyGuard {
         returns (uint256)
     {
         if (totalDscMinted == 0) return type(uint256).max;
-        uint256 collateralAdjustedForThreshold = (collateralValueInUsd * LIQUIDATION_THRESHOLD) / 100;
-        return (collateralAdjustedForThreshold * 1e18) / totalDscMinted;
+        uint256 collateralAdjustedForThreshold = (collateralValueInUsd * LIQUIDATION_THRESHOLD) / LIQUIDATION_PRECISION;
+        return (collateralAdjustedForThreshold * PRECISION) / totalDscMinted;
     }
 
     function revertIfHealthFactorIsBroken(address user) internal view {
@@ -395,6 +396,10 @@ contract DSCEngine is ReentrancyGuard {
         return LIQUIDATION_BONUS;
     }
 
+    function getLiquidationPrecision() external pure returns (uint256) {
+        return LIQUIDATION_PRECISION;
+    }
+
     function getMinHealthFactor() external pure returns (uint256) {
         return MIN_HEALTH_FACTOR;
     }

diff --git a/test/unit/DSCEngineTest.t.sol b/test/unit/DSCEngineTest.t.sol
@@ -552,6 +552,12 @@ contract DSCEngineTest is StdCheats, Test {
         assertEq(dscAddress, address(dsc));
     }
 
+    function testLiquidationPrecision() public {
+        uint256 expectedLiquidationPrecision = 100;
+        uint256 actualLiquidationPrecision = dsce.getLiquidationPrecision();
+        assertEq(actualLiquidationPrecision, expectedLiquidationPrecision);
+    }
+
     // How do we adjust our invariant tests for this?
     // function testInvariantBreaks() public depositedCollateralAndMintedDsc {
     //     MockV3Aggregator(ethUsdPriceFeed).updateAnswer(0);