Merge pull request #234 from VenusProtocol/feat/ven-2808

[VEN-2808] ERC4626 Oracle

contracts/interfaces/IERC4626.sol

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+// SPDX-License-Identifier: BSD-3-Clause
+pragma solidity 0.8.25;
+
+interface IERC4626 {
+    function convertToAssets(uint256 shares) external view returns (uint256);
+    function decimals() external view returns (uint8);
+}

contracts/oracles/ERC4626Oracle.sol

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+// SPDX-License-Identifier: BSD-3-Clause
+pragma solidity 0.8.25;
+
+import { IERC4626 } from "../interfaces/IERC4626.sol";
+import { CorrelatedTokenOracle } from "./common/CorrelatedTokenOracle.sol";
+import { EXP_SCALE } from "@venusprotocol/solidity-utilities/contracts/constants.sol";
+
+/**
+ * @title ERC4626Oracle
+ * @author Venus
+ * @notice This oracle fetches the price of ERC4626 tokens
+ */
+contract ERC4626Oracle is CorrelatedTokenOracle {
+    /// @notice Constructor for the implementation contract.
+    /// @custom:oz-upgrades-unsafe-allow constructor
+    constructor(
+        address correlatedToken,
+        address underlyingToken,
+        address resilientOracle
+    ) CorrelatedTokenOracle(correlatedToken, underlyingToken, resilientOracle) {}
+
+    /**
+     * @notice Fetches the amount of underlying token for 1 correlated token
+     * @return amount The amount of underlying token for correlated token
+     */
+    function _getUnderlyingAmount() internal view override returns (uint256) {
+        return IERC4626(CORRELATED_TOKEN).convertToAssets(EXP_SCALE);
+    }
+}

test/ERC4626Oracle.ts

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+import { smock } from "@defi-wonderland/smock";
+import chai from "chai";
+import { parseUnits } from "ethers/lib/utils";
+import { ethers } from "hardhat";
+
+import { ADDRESSES } from "../helpers/deploymentConfig";
+import { BEP20Harness, IERC4626, ResilientOracleInterface } from "../typechain-types";
+import { addr0000 } from "./utils/data";
+
+const { expect } = chai;
+chai.use(smock.matchers);
+
+const { FRAX, sFRAX } = ADDRESSES.ethereum;
+const FRAX_USD_PRICE = parseUnits("0.9979", 18); // 0.99 USD for 1 FRAX
+
+describe("ERC4626Oracle unit tests", () => {
+  let sFraxMock;
+  let resilientOracleMock;
+  let ERC4626OracleFactory;
+  let ERC4626Oracle;
+  let fraxMock;
+  before(async () => {
+    //  To initialize the provider we need to hit the node with any request
+    await ethers.getSigners();
+    resilientOracleMock = await smock.fake<ResilientOracleInterface>("ResilientOracleInterface");
+
+    sFraxMock = await smock.fake<IERC4626>("IERC4626", { address: sFRAX });
+    sFraxMock.convertToAssets.returns(parseUnits("1.019194969966192602", 18));
+    sFraxMock.decimals.returns(18);
+
+    fraxMock = await smock.fake<BEP20Harness>("BEP20Harness", { address: FRAX });
+    fraxMock.decimals.returns(18);
+
+    ERC4626OracleFactory = await ethers.getContractFactory("ERC4626Oracle");
+  });
+
+  describe("deployment", () => {
+    it("revert if FRAX address is 0", async () => {
+      await expect(ERC4626OracleFactory.deploy(sFraxMock.address, addr0000, resilientOracleMock.address)).to.be
+        .reverted;
+    });
+    it("revert if sFRAX address is 0", async () => {
+      await expect(ERC4626OracleFactory.deploy(addr0000, fraxMock.address, resilientOracleMock.address)).to.be.reverted;
+    });
+    it("should deploy contract", async () => {
+      ERC4626Oracle = await ERC4626OracleFactory.deploy(
+        sFraxMock.address,
+        fraxMock.address,
+        resilientOracleMock.address,
+      );
+    });
+  });
+
+  describe("getPrice", () => {
+    it("revert if address is not valid sFrax address", async () => {
+      await expect(ERC4626Oracle.getPrice(addr0000)).to.be.revertedWithCustomError(
+        ERC4626Oracle,
+        "InvalidTokenAddress",
+      );
+    });
+
+    it("should get correct price of sFrax", async () => {
+      resilientOracleMock.getPrice.returns(FRAX_USD_PRICE);
+      const price = await ERC4626Oracle.getPrice(sFraxMock.address);
+      expect(price).to.equal(parseUnits("1.017054660529263597", 18));
+    });
+  });
+});