updated fee policy to allow non-zero fees when dr is inside expected range (#258)

Author: aalavandhan

spot-contracts/contracts/FeePolicy.sol

@@ -175,9 +175,6 @@ contract FeePolicy is IFeePolicy, OwnableUpgradeable {
         // Expect DR to be non-decreasing, x1 <= x2
         bool validFees = ((feeFnDRDown_.x1 <= feeFnDRDown_.x2) && (feeFnDRUp_.x1 <= feeFnDRUp_.x2));
 
-        // Expect equilibrium zone to be valid
-        validFees = ((feeFnDRDown_.x2 <= ONE) && (feeFnDRUp_.x1 >= ONE)) && validFees;
-
         // Expect fees to be non-decreasing when dr moves away from 1.0
         validFees = ((feeFnDRDown_.y1 >= feeFnDRDown_.y2) && (feeFnDRUp_.y1 <= feeFnDRUp_.y2)) && validFees;
 

spot-contracts/test/FeePolicy.ts

@@ -148,20 +148,6 @@ describe("FeePolicy", function () {
         );
       });
 
-      it("equilibrium zone crosses 1.0", async function () {
-        const badDown = toLine("0.0", "1.0", "1.1", "0.0");
-        await expect(feePolicy.connect(deployer).updateFees(badDown, VALID_UP)).to.be.revertedWithCustomError(
-          feePolicy,
-          "InvalidFees",
-        );
-
-        const badUp = toLine("0.9", "0.0", "2.0", "1.0");
-        await expect(feePolicy.connect(deployer).updateFees(VALID_DOWN, badUp)).to.be.revertedWithCustomError(
-          feePolicy,
-          "InvalidFees",
-        );
-      });
-
       it("fees not monotonic wrt distance from 1.0", async function () {
         const badDown = toLine("0.0", "0.0", "1.0", "1.0");
         await expect(feePolicy.connect(deployer).updateFees(badDown, VALID_UP)).to.be.revertedWithCustomError(