Merge pull request #62 from euler-xyz/zero-amount-quotes

ensure quotes for 0 amount swaps return exactly 0

Author: hoytech

src/QuoteLib.sol

@@ -29,6 +29,8 @@ library QuoteLib {
         view
         returns (uint256)
     {
+        if (amount == 0) return 0;
+
         require(IEVC(evc).isAccountOperatorAuthorized(p.eulerAccount, address(this)), OperatorNotInstalled());
         require(amount <= type(uint112).max, SwapLimitExceeded());
 

test/Periphery.t.sol

@@ -120,4 +120,12 @@ contract PeripheryTest is EulerSwapTestBase {
 
         assertEq(assetTST2.balanceOf(anyone), amountOut);
     }
+
+    function test_SwapZeroAmounts() public view {
+        assertEq(periphery.quoteExactInput(address(eulerSwap), address(assetTST), address(assetTST2), 0), 0);
+        assertEq(periphery.quoteExactInput(address(eulerSwap), address(assetTST2), address(assetTST), 0), 0);
+
+        assertEq(periphery.quoteExactOutput(address(eulerSwap), address(assetTST), address(assetTST2), 0), 0);
+        assertEq(periphery.quoteExactOutput(address(eulerSwap), address(assetTST2), address(assetTST), 0), 0);
+    }
 }