fix(oracle): prevent instanciating with zero decimals

Author: Rubilmax

src/ChainlinkOracle.sol

@@ -59,7 +59,7 @@ contract ChainlinkOracle is IOracle {
         require(
             address(vault) != address(0) || vaultConversionSample == 1, ErrorsLib.VAULT_CONVERSION_SAMPLE_IS_NOT_ONE
         );
-        require(vaultConversionSample != 0, ErrorsLib.VAULT_CONVERSION_IS_ZERO);
+        require(vaultConversionSample != 0, ErrorsLib.VAULT_CONVERSION_SAMPLE_IS_ZERO);
 
         VAULT = vault;
         VAULT_CONVERSION_SAMPLE = vaultConversionSample;
@@ -97,7 +97,7 @@ contract ChainlinkOracle is IOracle {
             ** (
                 36 + quoteTokenDecimals + quoteFeed1.getDecimals() + quoteFeed2.getDecimals() - baseTokenDecimals
                     - baseFeed1.getDecimals() - baseFeed2.getDecimals()
-            ) / VAULT_CONVERSION_SAMPLE;
+            ) / vaultConversionSample;
     }
 
     /* PRICE */

test/ChainlinkOracleTest.sol

@@ -132,8 +132,14 @@ contract ChainlinkOracleTest is Test {
         assertApproxEqRel(oracle.price(), expectedPrice, deviation);
     }
 
+    function testConstructorZeroVaultConversionSample() public {
+        vm.expectRevert(bytes(ErrorsLib.VAULT_CONVERSION_SAMPLE_IS_ZERO));
+        new ChainlinkOracle(sDaiVault, daiEthFeed, feedZero, usdcEthFeed, feedZero, 0, 18, 6);
+    }
+
     function testConstructorVaultZeroNonOneSample(uint256 vaultConversionSample) public {
-        vm.assume(vaultConversionSample != 1);
+        vm.assume(vaultConversionSample > 1);
+
         vm.expectRevert(bytes(ErrorsLib.VAULT_CONVERSION_SAMPLE_IS_NOT_ONE));
         new ChainlinkOracle(vaultZero, daiEthFeed, feedZero, usdcEthFeed, feedZero, vaultConversionSample, 18, 6);
     }