test: add Ownable 'transferOwnership' fuzz tests

foundry.toml

@@ -10,6 +10,10 @@ ast = true
 build_info = true
 extra_output = ["storageLayout"]
 
+[profile.default.fuzz]
+max_test_rejects = 500_000
+runs = 100
+
 [fmt]
 bracket_spacing = true
 int_types = "long"

test/unit/concrete/ownable/transfer-ownership/transferOwnership.t.sol

@@ -21,12 +21,6 @@ contract TransferOwnership_Unit_Concrete_Test is Ownable_Shared_Test {
         ownableMock.transferOwnership({ newOwner: users.eve });
     }
 
-    modifier whenCallerCurrentOwner() {
-        // Make Admin the caller for the next test suite
-        vm.startPrank({ msgSender: users.admin });
-        _;
-    }
-
     function test_RevertWhen_NewOwnerZeroAddress() external whenCallerCurrentOwner {
         // Expect the next call to revert with the {InvalidOwnerZeroAddress} error
         vm.expectRevert(Errors.InvalidOwnerZeroAddress.selector);
@@ -35,10 +29,6 @@ contract TransferOwnership_Unit_Concrete_Test is Ownable_Shared_Test {
         ownableMock.transferOwnership({ newOwner: address(0x0) });
     }
 
-    modifier whenNewOwnerNotZeroAddress() {
-        _;
-    }
-
     function test_TransferOwnership() external whenCallerCurrentOwner whenNewOwnerNotZeroAddress {
         // Expect the {OwnershipTransferred} event to be emitted
         vm.expectEmit();

test/unit/fuzz/transferOwnership.t.sol

@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity ^0.8.26;
+
+import { Ownable_Shared_Test } from "../shared/Ownable.t.sol";
+import { Errors } from "../../utils/Errors.sol";
+import { Events } from "../../utils/Events.sol";
+
+contract TransferOwnership_Unit_Fuzz_Test is Ownable_Shared_Test {
+    function setUp() public virtual override {
+        Ownable_Shared_Test.setUp();
+    }
+
+    function testFuzz_RevertWhen_CallerNotCurrentOwner(address newOwner) external whenNewOwnerNotZeroAddress {
+        // Make sure the new owner is not the current one or the zero address
+        vm.assume(newOwner != users.admin && newOwner != address(0));
+
+        // Make Bob the caller for this test suite who is not the current owner
+        vm.startPrank({ msgSender: newOwner });
+
+        // Expect the next call to revert with the {Unauthorized} error
+        vm.expectRevert(Errors.Unauthorized.selector);
+
+        // Run the test
+        ownableMock.transferOwnership(newOwner);
+    }
+
+    function testFuzz_TransferOwnership(address newOwner) external whenCallerCurrentOwner whenNewOwnerNotZeroAddress {
+        // Make sure the new owner is not the zero address
+        vm.assume(newOwner != address(0));
+
+        // Expect the {OwnershipTransferred} event to be emitted
+        vm.expectEmit();
+        emit Events.OwnershipTransferred({ oldOwner: users.admin, newOwner: newOwner });
+
+        // Run the test
+        ownableMock.transferOwnership({ newOwner: newOwner });
+
+        // Assert the actual and expected owner
+        address actualOwner = ownableMock.owner();
+        assertEq(actualOwner, newOwner);
+    }
+}

test/unit/shared/Ownable.t.sol

@@ -11,4 +11,14 @@ contract Ownable_Shared_Test is Base_Test {
         Base_Test.setUp();
         ownableMock = new OwnableMock({ _owner: users.admin });
     }
+
+    modifier whenCallerCurrentOwner() {
+        // Make Admin the caller for the next test suite
+        vm.startPrank({ msgSender: users.admin });
+        _;
+    }
+
+    modifier whenNewOwnerNotZeroAddress() {
+        _;
+    }
 }