test: Add MinterCommitEmissionTest for emission rate update (#811)

* test: Add MinterCommitEmissionTest for emission rate update

* test: Update test comments

.gitmodules

@@ -1,3 +1,5 @@
 [submodule "lib/forge-std"]
 	path = lib/forge-std
 	url = https://github.com/foundry-rs/forge-std
+	branch = v1
+

foundry.toml

@@ -1,6 +1,5 @@
 [profile.default]
 src = 'contracts'
-out = 'out'
 libs = ["node_modules", "lib"]
 test = 'test/foundry'
 remappings = [

test/foundry/MinterCommitEmissionTest.sol

@@ -0,0 +1,101 @@
+// SPDX-License-Identifier: MIT
+pragma solidity 0.8.17;
+
+import {TestWithConstants} from "../../forge-script/TestWithConstants.sol";
+import {console2 as console} from "forge-std/console2.sol";
+
+interface IMinter {
+    function rate() external view returns (uint256);
+
+    function committed_rate() external view returns (uint256);
+
+    function commit_next_emission(uint256) external;
+
+    function admin() external view returns (address);
+
+    function mint(address) external;
+
+    function start_epoch_time_write() external returns (uint256);
+
+    function update_mining_parameters() external;
+
+    function start_epoch_time() external view returns (uint256);
+}
+
+interface IRootGuage {
+    struct InflationParams {
+        uint256 rate;
+        uint256 finish_time;
+    }
+
+    function inflation_params() external view returns (InflationParams memory);
+}
+
+interface ILiquidityGaugeV5 {
+    function inflation_rate() external view returns (uint256);
+}
+
+contract MinterCommitEmissionTest is TestWithConstants {
+    IMinter public minter;
+    address public minterAdmin;
+    IRootGuage public rootGauge;
+    ILiquidityGaugeV5 public liqGaugeV5;
+
+    function setUp() public override {
+        super.setUp();
+        // Fork mainnet at block 17565727
+        vm.createSelectFork("mainnet", 17565727);
+        minter = IMinter(getDeploymentAddress("Minter"));
+        liqGaugeV5 = ILiquidityGaugeV5(
+            getDeploymentAddress(
+                "LiquidityGaugeV5_SaddleFRAXalUSDMetaPoolLPToken"
+            )
+        );
+        rootGauge = IRootGuage(
+            getDeploymentAddress("RootGauge_42161_SaddleFRAXBPPoolLPToken")
+        );
+        minterAdmin = minter.admin();
+
+        vm.label(address(minter), "Minter");
+    }
+
+    // Test lowering the emission rate applies the new rate after the next mining epoch
+    // and the new rate is applied to the gauges of both types
+    function test_commitEmission() public {
+        vm.startPrank(minterAdmin);
+        // Assert that the current rate is 30M / 24 weeks
+        uint256 currentRate = minter.rate();
+        assertEq(currentRate, (uint256(30_000_000 * 1e18) / 24) / 1 weeks);
+        console.log("current rate: %s", currentRate);
+        console.log("current commited_rate: %s", minter.committed_rate());
+
+        // Apply the new rate of 20M / 24 weeks
+        uint256 nextWeeklyRate = (uint256(20_000_000 * 1e18) / 24);
+        minter.commit_next_emission(nextWeeklyRate);
+
+        // Assert that the commited rate is updated but the rate is not updated yet
+        uint256 commitedRate = minter.committed_rate();
+        assertEq(commitedRate, nextWeeklyRate / 1 weeks);
+        assertEq(minter.rate(), currentRate);
+
+        // Skip to next mining epoch which is in every 2 weeks
+        // Since voting epoch is every 1 week, there may be a week with old rate until
+        // the next mining epoch starts that applies the new rate
+        vm.warp(((block.timestamp + 2 weeks) / 1 weeks) * 1 weeks);
+
+        // Update mining parameters manually to ensure that the rate is updated
+        minter.update_mining_parameters();
+
+        // Ensure that the rate is updated with the commited rate
+        uint256 newRate = minter.rate();
+        assertEq(newRate, commitedRate);
+
+        // Mint for liqGaugeV5 type gauge and expect that the internal rate var is updated
+        minter.mint(address(liqGaugeV5));
+        assertEq(newRate, liqGaugeV5.inflation_rate());
+
+        // Mint for rootGauge type gauge and expect that the internal rate var is updated
+        minter.mint(address(rootGauge));
+        assertEq(newRate, rootGauge.inflation_params().rate);
+    }
+}