improve tests SystemConfig (#12938)

* improve tests

* improve tests

* fixes

packages/contracts-bedrock/test/L1/SystemConfig.t.sol

@@ -255,6 +255,19 @@ contract SystemConfig_Init_ResourceConfig is SystemConfig_Init {
         _initializeWithResourceConfig(config, "SystemConfig: gas limit too low");
     }
 
+    /// @dev Tests that `setResourceConfig` reverts if the gas limit is too low.
+    function test_setResourceConfig_elasticityMultiplierIs0_reverts() external {
+        IResourceMetering.ResourceConfig memory config = IResourceMetering.ResourceConfig({
+            maxResourceLimit: 20_000_000,
+            elasticityMultiplier: 0,
+            baseFeeMaxChangeDenominator: 8,
+            systemTxMaxGas: 1_000_000,
+            minimumBaseFee: 1 gwei,
+            maximumBaseFee: 2 gwei
+        });
+        _initializeWithResourceConfig(config, "SystemConfig: elasticity multiplier cannot be 0");
+    }
+
     /// @dev Tests that `setResourceConfig` reverts if the elasticity multiplier
     ///      and max resource limit are configured such that there is a loss of precision.
     function test_setResourceConfig_badPrecision_reverts() external {

packages/contracts-bedrock/test/L1/SystemConfigInterop.t.sol

@@ -26,6 +26,19 @@ contract SystemConfigInterop_Test is CommonTest {
         super.setUp();
     }
 
+    /// @dev Tests that when the decimals is not 18, initialization reverts.
+    function test_initialize_decimalsIsNot18_reverts(uint8 decimals) external {
+        vm.assume(decimals != 18);
+        address _token = address(L1Token);
+
+        vm.mockCall(_token, abi.encodeCall(ERC20.name, ()), abi.encode("Token"));
+        vm.mockCall(_token, abi.encodeCall(ERC20.symbol, ()), abi.encode("TKN"));
+        vm.mockCall(_token, abi.encodeCall(ERC20.decimals, ()), abi.encode(decimals));
+
+        vm.expectRevert("SystemConfig: bad decimals of gas paying token");
+        _cleanStorageAndInit(_token);
+    }
+
     /// @dev Tests that the gas paying token can be set.
     function testFuzz_setGasPayingToken_succeeds(
         address _token,