VAL-131 (Part 2) Add methods for previewing withdraw/redeem request fees

contracts/Pool.sol

@@ -475,6 +475,17 @@ contract Pool is IPool, ERC20Upgradeable, BeaconImplementation {
         assets = withdrawController.previewRedeemRequest(shares);
     }
 
+    /**
+     * @inheritdoc IRequestWithdrawable
+     */
+    function previewRedeemRequestFees(uint256 shares)
+        external
+        view
+        returns (uint256 feeShares)
+    {
+        feeShares = withdrawController.previewRedeemRequestFees(shares);
+    }
+
     /**
      * @inheritdoc IRequestWithdrawable
      */
@@ -486,6 +497,17 @@ contract Pool is IPool, ERC20Upgradeable, BeaconImplementation {
         shares = withdrawController.previewWithdrawRequest(assets);
     }
 
+    /**
+     * @inheritdoc IRequestWithdrawable
+     */
+    function previewWithdrawRequestFees(uint256 assets)
+        external
+        view
+        returns (uint256 feeShares)
+    {
+        feeShares = withdrawController.previewWithdrawRequestFees(assets);
+    }
+
     /**
      * @inheritdoc IRequestWithdrawable
      */

contracts/controllers/WithdrawController.sol

@@ -209,12 +209,21 @@ contract WithdrawController is IWithdrawController, BeaconImplementation {
         view
         returns (uint256 assets)
     {
-        uint256 shareFees = PoolLib.calculateRequestFee(
+        assets = _pool.convertToAssets(shares);
+    }
+
+    /**
+     * @inheritdoc IWithdrawController
+     */
+    function previewRedeemRequestFees(uint256 shares)
+        external
+        view
+        returns (uint256 feeShares)
+    {
+        feeShares = PoolLib.calculateRequestFee(
             shares,
             _pool.settings().requestFeeBps
         );
-
-        assets = _pool.convertToAssets(shares - shareFees);
     }
 
     /**
@@ -224,13 +233,24 @@ contract WithdrawController is IWithdrawController, BeaconImplementation {
         external
         view
         returns (uint256 shares)
+    {
+        shares = _pool.convertToShares(assets);
+    }
+
+    /**
+     * @inheritdoc IWithdrawController
+     */
+    function previewWithdrawRequestFees(uint256 assets)
+        external
+        view
+        returns (uint256 feeShares)
     {
         uint256 assetFees = PoolLib.calculateRequestFee(
             assets,
             _pool.settings().requestFeeBps
         );
 
-        shares = _pool.convertToShares(assets + assetFees);
+        feeShares = _pool.convertToShares(assetFees);
     }
 
     /**

contracts/controllers/interfaces/IWithdrawController.sol

@@ -116,6 +116,16 @@ interface IWithdrawController {
      */
     function previewRedeemRequest(uint256) external view returns (uint256);
 
+    /**
+     * @dev Returns the amount of fees (shares) that would be required to process
+     * a redeem request at this current block.
+     *
+     */
+    function previewRedeemRequestFees(uint256 shares)
+        external
+        view
+        returns (uint256 feeShares);
+
     /**
      * @dev Simulate the effects of a withdrawal request at the current block.
      * Returns the amount of `shares` that would be burned if this entire
@@ -125,6 +135,15 @@ interface IWithdrawController {
      */
     function previewWithdrawRequest(uint256) external view returns (uint256);
 
+    /**
+     * @dev Returns the amount of fees that would be burned, in shares, to fulfill
+     * a withdraw request in this current block.
+     */
+    function previewWithdrawRequestFees(uint256 assets)
+        external
+        view
+        returns (uint256 feeShares);
+
     /**
      * @dev Simulates the effects of their redeemption at the current block.
      * Per EIP4626, should round DOWN.

contracts/interfaces/IRequestWithdrawable.sol

@@ -44,6 +44,16 @@ interface IRequestWithdrawable {
         view
         returns (uint256 assets);
 
+    /**
+     * @dev Returns the amount of fees (shares) that would be required to process
+     * a redeem request at this current block.
+     *
+     */
+    function previewRedeemRequestFees(uint256 shares)
+        external
+        view
+        returns (uint256 feeShares);
+
     /**
      * @dev Simulate the effects of a withdrawal request at the current block.
      * Returns the amount of `shares` that would be burned if this entire
@@ -56,6 +66,15 @@ interface IRequestWithdrawable {
         view
         returns (uint256 shares);
 
+    /**
+     * @dev Returns the amount of fees that would be burned, in shares, to fulfill
+     * a withdraw request in this current block.
+     */
+    function previewWithdrawRequestFees(uint256 assets)
+        external
+        view
+        returns (uint256 feeShares);
+
     /**
      * @dev Submits a withdrawal request, incurring a fee.
      */

test/Pool.test.ts

@@ -642,13 +642,19 @@ describe("Pool", () => {
     });
 
     describe("previewRedeemRequest", () => {
-      it("returns the number of assets, minus fees, rounded down, that would be transferred in this redeem request, regardless of caller balance", async () => {
-        const { pool, poolController, poolAdmin, liquidityAsset } =
-          await loadFixture(loadPoolFixture);
-        await poolController.connect(poolAdmin).setRequestFee(1000); // 10%
-        await activatePool(pool, poolAdmin, liquidityAsset);
+      it("returns the number of assets that would be transferred in this redeem request", async () => {
+        const { pool } = await loadFixture(loadPoolFixture);
+        expect(await pool.previewRedeemRequest(27)).to.equal(27);
+      });
+    });
 
-        expect(await pool.previewRedeemRequest(27)).to.equal(24);
+    describe("previewRedeemRequestFees(assets)", () => {
+      it("returns the fees required to request shares for redemption", async () => {
+        const { pool, poolController, poolAdmin } = await loadFixture(
+          loadPoolFixture
+        );
+        await poolController.connect(poolAdmin).setRequestFee(1000); // 10%
+        expect(await pool.previewRedeemRequestFees(30)).to.equal(3);
       });
     });
 
@@ -786,12 +792,19 @@ describe("Pool", () => {
 
     describe("previewWithdrawRequest(assets)", () => {
       it("returns the share value of the provided assets, minus fees, regardless of caller balance", async () => {
-        const { pool, poolController, poolAdmin, liquidityAsset } =
-          await loadFixture(loadPoolFixture);
-        await poolController.connect(poolAdmin).setRequestFee(1000); // 10%
-        await activatePool(pool, poolAdmin, liquidityAsset);
+        const { pool } = await loadFixture(loadPoolFixture);
+
+        expect(await pool.previewWithdrawRequest(30)).to.equal(30);
+      });
+    });
 
-        expect(await pool.previewWithdrawRequest(27)).to.equal(30);
+    describe("previewWithdrawRequestFees(assets)", () => {
+      it("returns the fees required to request assets for withdrawal", async () => {
+        const { pool, poolController, poolAdmin } = await loadFixture(
+          loadPoolFixture
+        );
+        await poolController.connect(poolAdmin).setRequestFee(1000); // 10%
+        expect(await pool.previewWithdrawRequestFees(30)).to.equal(3);
       });
     });
 

test/scenarios/pool/direct-deposit.test.ts

@@ -70,10 +70,18 @@ describe("Direct Deposit", () => {
 
     // Check withdrawal amounts
     expect(await pool.connect(lender).previewWithdrawRequest(100_000)).to.equal(
-      52_500 // 50_000 plus fees
+      50_000
     );
+    expect(
+      await pool.connect(lender).previewWithdrawRequestFees(100_000)
+    ).to.equal(2_500);
     expect(await pool.connect(lender).previewRedeemRequest(100_000)).to.equal(
-      190_000 // 200_000 minus fees
+      200_000
+    );
+    expect(
+      await pool.connect(lender).previewRedeemRequestFees(100_000)
+    ).to.equal(
+      5_000 // 5k shares, aka 10k assets
     );
   });
 
@@ -105,10 +113,18 @@ describe("Direct Deposit", () => {
 
     // Check withdrawal amounts
     expect(await pool.connect(lender).previewWithdrawRequest(100_000)).to.equal(
-      52_500 // 50_000 plus fees
+      50_000
     );
+    expect(
+      await pool.connect(lender).previewWithdrawRequestFees(100_000)
+    ).to.equal(2_500);
     expect(await pool.connect(lender).previewRedeemRequest(100_000)).to.equal(
-      190_000 // 200_000 minus fees
+      200_000
+    );
+    expect(
+      await pool.connect(lender).previewRedeemRequestFees(100_000)
+    ).to.equal(
+      5_000 // 5k shares, aka 10k assets
     );
   });