fix: error message

Author: MathisGD

src/ChainlinkOracle.sol

@@ -5,6 +5,7 @@ import {IOracle} from "morpho-blue/interfaces/IOracle.sol";
 
 import {AggregatorV3Interface, ChainlinkDataFeedLib} from "./libraries/ChainlinkDataFeedLib.sol";
 import {IERC4626, VaultLib} from "./libraries/VaultLib.sol";
+import {ErrorsLib} from "./libraries/ErrorsLib.sol";
 
 /// @title ChainlinkOracle
 /// @author Morpho Labs
@@ -56,7 +57,7 @@ contract ChainlinkOracle is IOracle {
         // It is used to price `VAULT_CONVERSION_SAMPLE` of the vault shares, so it requires dividing by that number,
         // hence the division by `VAULT_CONVERSION_SAMPLE` in the `SCALE_FACTOR` definition.
         // Verify that vault = 0 => vaultConversionSample = 1.
-        require(address(vault) != address(0) || vaultConversionSample == 1);
+        require(address(vault) != address(0) || vaultConversionSample == 1, ErrorsLib.VAULT_CONVERSION_SAMPLE_IS_NOT_ONE);
         VAULT = vault;
         VAULT_CONVERSION_SAMPLE = vaultConversionSample;
         BASE_FEED_1 = baseFeed1;

src/libraries/ErrorsLib.sol

@@ -8,4 +8,7 @@ pragma solidity ^0.8.0;
 library ErrorsLib {
     /// @notice Thrown when the answer returned by a Chainlink feed is negative.
     string constant NEGATIVE_ANSWER = "negative answer";
+
+    /// @notice Thrown when the vault conversion sample is not 1 while vault = 0.
+    string constant VAULT_CONVERSION_SAMPLE_IS_NOT_ONE = "vault conversion sample is not one";
 }

test/ChainlinkOracleTest.sol

@@ -134,7 +134,7 @@ contract ChainlinkOracleTest is Test {
 
     function testConstructorVaultZeroNonOneSample(uint256 vaultConversionSample) public {
         vm.assume(vaultConversionSample != 1);
-        vm.expectRevert();
+        vm.expectRevert(bytes(ErrorsLib.VAULT_CONVERSION_SAMPLE_IS_NOT_ONE));
         new ChainlinkOracle(vaultZero, daiEthFeed, feedZero, usdcEthFeed, feedZero, vaultConversionSample, 18, 6);
     }
 }