test(pool-monitor): add pool monitor initial test

packages/contracts/test/dollar/monitors/PoolLiquidityMonitorTest.t.sol

@@ -0,0 +1,32 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.19;
+
+import "forge-std/Test.sol";
+import "../../../src/dollar/monitors/PoolLiquidityMonitor.sol";
+import "../../helpers/LocalTestHelper.sol";
+
+contract PoolLiquidityMonitorTest is LocalTestHelper {
+    PoolLiquidityMonitor monitor;
+    address defenderRelayer = address(0x456);
+
+    function setUp() public override {
+        super.setUp();
+
+        monitor = new PoolLiquidityMonitor(
+            address(ubiquityPoolFacet),
+            defenderRelayer
+        );
+    }
+
+    function testInitialSetup() public {
+        assertEq(monitor.defenderRelayer(), defenderRelayer);
+    }
+
+    function testSetDefenderRelayer() public {
+        address newRelayer = address(0x789);
+
+        monitor.setDefenderRelayer(newRelayer);
+
+        assertEq(monitor.defenderRelayer(), newRelayer);
+    }
+}