feat: Add SimplePlusAccountFactory test suite

test/SimplePlusAccountFactory.t.sol

@@ -0,0 +1,37 @@
+// SPDX-License-Identifier: GPL-3.0
+pragma solidity ^0.8.23;
+
+import { Test } from "forge-std/src/Test.sol";
+
+import { EntryPoint } from "@account-abstraction/contracts/core/EntryPoint.sol";
+
+import { SimplePlusAccount } from "../src/SimplePlusAccount.sol";
+import { SimplePlusAccountFactory } from "../src/SimplePlusAccountFactory.sol";
+
+contract SimplePlusAccountFactoryTest is Test {
+    address public constant OWNER_ADDRESS = address(0x100);
+    SimplePlusAccountFactory public factory;
+    EntryPoint public entryPoint;
+
+    function setUp() public {
+        entryPoint = new EntryPoint();
+        factory = new SimplePlusAccountFactory(entryPoint);
+    }
+
+    function testReturnsAddressWhenAccountAlreadyExists() public {
+        SimplePlusAccount account = factory.createAccount(OWNER_ADDRESS, 1);
+        SimplePlusAccount otherAccount = factory.createAccount(OWNER_ADDRESS, 1);
+        assertEq(address(account), address(otherAccount));
+    }
+
+    function testGetAddress() public {
+        address counterfactual = factory.getAddress(OWNER_ADDRESS, 1);
+        assertEq(counterfactual.codehash, bytes32(0));
+        SimplePlusAccount factual = factory.createAccount(OWNER_ADDRESS, 1);
+        assertTrue(address(factual).codehash != bytes32(0));
+        assertEq(counterfactual, address(factual));
+    }
+
+    /// @dev Receive funds from withdraw.
+    receive() external payable { }
+}