From ff7d9fe9618c26b270d498e3d04c1a34b3bb0271 Mon Sep 17 00:00:00 2001
From: PThorpe92 <preston@turso.tech>
Date: Tue, 5 Aug 2025 12:51:17 -0400
Subject: [PATCH] Add basic test for buffer pool initialization and basic use

---
 core/storage/buffer_pool.rs | 83 +++++++++++++++++++++++++++++++++++++
 1 file changed, 83 insertions(+)

diff --git a/core/storage/buffer_pool.rs b/core/storage/buffer_pool.rs
index f2802febe..b08074d19 100644
--- a/core/storage/buffer_pool.rs
+++ b/core/storage/buffer_pool.rs
@@ -513,3 +513,86 @@ mod arena {
         unsafe { std::alloc::dealloc(ptr, layout) };
     }
 }
+
+#[cfg(test)]
+pub mod tests {
+    use super::*;
+    const TEST_SIZE: usize = 4096 * 50;
+
+    #[test]
+    fn test_init_pool() {
+        let io: Arc<dyn crate::IO> = Arc::new(crate::MemoryIO::new());
+        let pool = BufferPool::begin_init(&io, TEST_SIZE);
+        pool.finalize_with_page_size(BufferPool::DEFAULT_PAGE_SIZE)
+            .expect("pool to initialize");
+        assert_eq!(pool.get_page().len(), BufferPool::DEFAULT_PAGE_SIZE);
+        assert_eq!(
+            pool.get_wal_frame().len(),
+            BufferPool::DEFAULT_ARENA_SIZE + WAL_FRAME_HEADER_SIZE,
+            "get_wal_frame should return page_size + WAL_FRAME_HEADER_SIZE"
+        );
+        assert!(
+            pool.inner_mut().page_arena.is_some(),
+            "page arena should be initialized"
+        );
+        assert!(
+            pool.inner_mut().wal_frame_arena.is_some(),
+            "wal frame arena should be initialized"
+        );
+        let inner = pool.inner_mut();
+        assert!(
+            inner
+                .page_arena
+                .as_ref()
+                .is_some_and(|a| a.id >= UNREGISTERED_START),
+            "page arena should not have ID in registered range with MemoryIO"
+        );
+        assert!(
+            inner
+                .wal_frame_arena
+                .as_ref()
+                .is_some_and(|a| a.id >= UNREGISTERED_START),
+            "wal frame arena should not have ID in registered range with MemoryIO"
+        );
+        let page = inner.get_page();
+        assert_eq!(
+            inner
+                .page_arena
+                .as_ref()
+                .unwrap()
+                .allocated_pages
+                .load(Ordering::Relaxed),
+            1
+        );
+        drop(page);
+        let frame = inner.get_frame();
+        assert_eq!(
+            inner
+                .wal_frame_arena
+                .as_ref()
+                .unwrap()
+                .allocated_pages
+                .load(Ordering::Relaxed),
+            1
+        );
+        drop(frame);
+        assert_eq!(
+            inner
+                .wal_frame_arena
+                .as_ref()
+                .unwrap()
+                .allocated_pages
+                .load(Ordering::Relaxed),
+            0
+        );
+        assert_eq!(
+            inner
+                .page_arena
+                .as_ref()
+                .unwrap()
+                .allocated_pages
+                .load(Ordering::Relaxed),
+            0
+        );
+    }
+}