diff --git a/src/include/storage/wal/wal.h b/src/include/storage/wal/wal.h
index fac314a918..4c6c592182 100644
--- a/src/include/storage/wal/wal.h
+++ b/src/include/storage/wal/wal.h
@@ -175,7 +175,7 @@ class WAL : public BaseWALAndWALIterator {
 
 class WALIterator : public BaseWALAndWALIterator {
 public:
-    explicit WALIterator(shared_ptr<FileHandle> fileHandle, mutex& mtx);
+    explicit WALIterator(const shared_ptr<FileHandle>& fileHandle, mutex& mtx);
 
     inline bool hasNextRecord() {
         lock_t lck{mtx};
diff --git a/src/storage/wal/wal.cpp b/src/storage/wal/wal.cpp
index 9d92013e94..412d4e35bc 100644
--- a/src/storage/wal/wal.cpp
+++ b/src/storage/wal/wal.cpp
@@ -155,7 +155,7 @@ void WAL::setIsLastRecordCommit() {
     }
 }
 
-WALIterator::WALIterator(shared_ptr<FileHandle> fileHandle, mutex& mtx)
+WALIterator::WALIterator(const shared_ptr<FileHandle>& fileHandle, mutex& mtx)
     : BaseWALAndWALIterator(fileHandle), mtx{mtx} {
     resetCurrentHeaderPagePrefix();
     if (fileHandle->getNumPages() > 0) {
diff --git a/test/include/main_test_helper/main_test_helper.h b/test/include/main_test_helper/main_test_helper.h
index adfcc93324..2f6556c8e0 100644
--- a/test/include/main_test_helper/main_test_helper.h
+++ b/test/include/main_test_helper/main_test_helper.h
@@ -5,11 +5,11 @@
 namespace kuzu {
 namespace testing {
 
-class ApiTest : public EmptyDBTest {
+class ApiTest : public BaseGraphTest {
 
 public:
     void SetUp() override {
-        EmptyDBTest::SetUp();
+        BaseGraphTest::SetUp();
         systemConfig->defaultPageBufferPoolSize = (1ull << 26);
         systemConfig->largePageBufferPoolSize = (1ull << 26);
         createDBAndConn();
diff --git a/test/include/test_helper/test_helper.h b/test/include/test_helper/test_helper.h
index 649648e412..480eb59f4e 100644
--- a/test/include/test_helper/test_helper.h
+++ b/test/include/test_helper/test_helper.h
@@ -74,6 +74,9 @@ class BaseGraphTest : public Test {
     void TearDown() override { FileUtils::removeDir(TestHelper::getTmpTestDir()); }
 
     inline void createDBAndConn() {
+        if (database != nullptr) {
+            database.reset();
+        }
         database = make_unique<Database>(*databaseConfig, *systemConfig);
         conn = make_unique<Connection>(database.get());
         spdlog::set_level(spdlog::level::info);
diff --git a/test/main/config_test.cpp b/test/main/config_test.cpp
index b7a46a2abf..6e9073e64e 100644
--- a/test/main/config_test.cpp
+++ b/test/main/config_test.cpp
@@ -3,19 +3,16 @@
 using namespace kuzu::testing;
 
 TEST_F(ApiTest, DatabaseConfig) {
-    auto db = make_unique<Database>(DatabaseConfig(TestHelper::getTmpTestDir()));
     spdlog::set_level(spdlog::level::debug);
-    ASSERT_NO_THROW(db->resizeBufferManager(StorageConfig::DEFAULT_BUFFER_POOL_SIZE * 2));
-    ASSERT_EQ(getDefaultBMSize(*db), (uint64_t)(StorageConfig::DEFAULT_BUFFER_POOL_SIZE * 2 *
-                                                StorageConfig::DEFAULT_PAGES_BUFFER_RATIO));
-    ASSERT_EQ(getLargeBMSize(*db), (uint64_t)(StorageConfig::DEFAULT_BUFFER_POOL_SIZE * 2 *
-                                              StorageConfig::LARGE_PAGES_BUFFER_RATIO));
+    ASSERT_NO_THROW(database->resizeBufferManager(StorageConfig::DEFAULT_BUFFER_POOL_SIZE * 2));
+    ASSERT_EQ(getDefaultBMSize(*database), (uint64_t)(StorageConfig::DEFAULT_BUFFER_POOL_SIZE * 2 *
+                                                      StorageConfig::DEFAULT_PAGES_BUFFER_RATIO));
+    ASSERT_EQ(getLargeBMSize(*database), (uint64_t)(StorageConfig::DEFAULT_BUFFER_POOL_SIZE * 2 *
+                                                    StorageConfig::LARGE_PAGES_BUFFER_RATIO));
 }
 
 TEST_F(ApiTest, ClientConfig) {
-    auto db = make_unique<Database>(DatabaseConfig(TestHelper::getTmpTestDir()));
     spdlog::set_level(spdlog::level::debug);
-    auto conn = make_unique<Connection>(db.get());
     ASSERT_NO_THROW(conn->setMaxNumThreadForExec(2));
     ASSERT_EQ(conn->getMaxNumThreadForExec(), 2);
 }