chore: migrate to GoogleTest and restore coverage

.github/workflows/ci.yml

@@ -73,13 +73,15 @@ jobs:
         ./transaction_manager_tests
         ./statement_tests
         ./recovery_tests
+        ./recovery_manager_tests
+        ./buffer_pool_tests
 
     - name: Generate Coverage Report
       if: matrix.sanitizer == 'address' && matrix.compiler == 'clang++'
       run: |
         cd build
         lcov --directory . --capture --output-file coverage.info --gcov-tool "$GITHUB_WORKSPACE/.github/scripts/llvm-gcov.sh" --ignore-errors inconsistent
-        lcov --remove coverage.info '/usr/*' '*/tests/*' '*/CMakeFiles/*' --output-file filtered_coverage.info --ignore-errors inconsistent,unused
+        lcov --remove coverage.info '/usr/*' '*/tests/*' '*/CMakeFiles/*' '*/_deps/*' --output-file filtered_coverage.info --ignore-errors inconsistent,unused
         genhtml filtered_coverage.info --output-directory out_coverage --ignore-errors inconsistent
 
     - name: Upload Coverage

include/storage/buffer_pool_manager.hpp

@@ -7,6 +7,7 @@
 #define CLOUDSQL_STORAGE_BUFFER_POOL_MANAGER_HPP
 
 #include <list>
+#include <memory>
 #include <mutex>
 #include <string>
 #include <unordered_map>
@@ -95,6 +96,11 @@ class BufferPoolManager {
      */
     void flush_all_pages();
 
+    /**
+     * @brief Get pointer to log manager
+     */
+    [[nodiscard]] recovery::LogManager* get_log_manager() const { return log_manager_; }
+
    private:
     /**
      * @brief Generates a unique string key for file and page mapping
@@ -111,7 +117,7 @@ class BufferPoolManager {
     std::mutex latch_;
 
     // The actual array of pages
-    std::vector<Page> pages_;
+    std::unique_ptr<Page[]> pages_;
 
     // Replacer instance
     LRUReplacer replacer_;

include/storage/storage_manager.hpp

@@ -73,6 +73,18 @@ class StorageManager {
      */
     bool write_page(const std::string& filename, uint32_t page_num, const char* buffer);
 
+    /**
+     * @brief Allocate a new page in the database file
+     * @param filename Name of the database file
+     * @return index of the newly allocated page
+     */
+    uint32_t allocate_page(const std::string& filename);
+
+    /**
+     * @brief Deallocate a page (stub for future use)
+     */
+    static void deallocate_page(const std::string& filename, uint32_t page_num);
+
     /**
      * @brief Check if a file exists
      */

include/transaction/transaction.hpp

@@ -109,11 +109,11 @@ class Transaction {
         exclusive_locks_.insert(rid);
     }
 
-    [[nodiscard]] const std::unordered_set<std::string>& get_shared_locks() {
+    [[nodiscard]] std::unordered_set<std::string> get_shared_lock_set() {
         const std::scoped_lock<std::mutex> lock(lock_set_mutex_);
         return shared_locks_;
     }
-    [[nodiscard]] const std::unordered_set<std::string>& get_exclusive_locks() {
+    [[nodiscard]] std::unordered_set<std::string> get_exclusive_lock_set() {
         const std::scoped_lock<std::mutex> lock(lock_set_mutex_);
         return exclusive_locks_;
     }

include/transaction/transaction_manager.hpp

@@ -7,41 +7,77 @@
 #define CLOUDSQL_TRANSACTION_TRANSACTION_MANAGER_HPP
 
 #include <atomic>
+#include <deque>
 #include <memory>
+#include <mutex>
 #include <unordered_map>
+#include <vector>
 
 #include "catalog/catalog.hpp"
-#include "recovery/log_manager.hpp"
 #include "storage/buffer_pool_manager.hpp"
 #include "transaction/lock_manager.hpp"
 #include "transaction/transaction.hpp"
 
 namespace cloudsql::transaction {
 
+/**
+ * @brief Manages the lifecycle of transactions
+ */
 class TransactionManager {
-   private:
-    std::atomic<txn_id_t> next_txn_id_{1};
-    std::unordered_map<txn_id_t, std::unique_ptr<Transaction>> active_transactions_;
-    std::unordered_map<txn_id_t, std::unique_ptr<Transaction>> completed_transactions_;
-    LockManager& lock_manager_;
-    Catalog& catalog_;
-    storage::BufferPoolManager& bpm_;
-    recovery::LogManager* log_manager_;
-    std::mutex manager_latch_;
-
-    void undo_transaction(Transaction* txn);
-
    public:
     explicit TransactionManager(LockManager& lock_manager, Catalog& catalog,
                                 storage::BufferPoolManager& bpm,
-                                recovery::LogManager* log_manager = nullptr)
-        : lock_manager_(lock_manager), catalog_(catalog), bpm_(bpm), log_manager_(log_manager) {}
+                                recovery::LogManager* log_manager = nullptr);
+
+    ~TransactionManager() = default;
 
+    // Disable copy/move
+    TransactionManager(const TransactionManager&) = delete;
+    TransactionManager& operator=(const TransactionManager&) = delete;
+    TransactionManager(TransactionManager&&) = delete;
+    TransactionManager& operator=(TransactionManager&&) = delete;
+
+    /**
+     * @brief Start a new transaction
+     * @param level Isolation level
+     * @return Pointer to the new transaction
+     */
     Transaction* begin(IsolationLevel level = IsolationLevel::REPEATABLE_READ);
+
+    /**
+     * @brief Commit a transaction
+     */
     void commit(Transaction* txn);
+
+    /**
+     * @brief Abort a transaction
+     */
     void abort(Transaction* txn);
 
+    /**
+     * @brief Get transaction by ID
+     */
     Transaction* get_transaction(txn_id_t txn_id);
+
+   private:
+    LockManager& lock_manager_;
+    Catalog& catalog_;
+    storage::BufferPoolManager& bpm_;
+    recovery::LogManager* log_manager_;
+
+    std::atomic<txn_id_t> next_txn_id_{1};
+    std::mutex manager_latch_;
+
+    // All active transactions
+    std::unordered_map<txn_id_t, std::unique_ptr<Transaction>> active_transactions_;
+
+    // Transactions that have recently finished (for cleanup/safety)
+    std::deque<std::unique_ptr<Transaction>> completed_transactions_;
+
+    /**
+     * @brief Undo changes made by a transaction
+     */
+    void undo_transaction(Transaction* txn);
 };
 
 }  // namespace cloudsql::transaction

src/catalog/catalog.cpp

@@ -15,6 +15,7 @@
 #include <iostream>
 #include <memory>
 #include <optional>
+#include <stdexcept>
 #include <string>
 #include <utility>
 #include <vector>
@@ -70,6 +71,10 @@ bool Catalog::save(const std::string& filename) const {
  * @brief Create a new table
  */
 oid_t Catalog::create_table(const std::string& table_name, std::vector<ColumnInfo> columns) {
+    if (table_exists_by_name(table_name)) {
+        throw std::runtime_error("Table already exists: " + table_name);
+    }
+
     auto table = std::make_unique<TableInfo>();
     table->table_id = next_oid_++;
     table->name = table_name;
@@ -139,6 +144,13 @@ oid_t Catalog::create_index(const std::string& index_name, oid_t table_id,
         return 0;
     }
 
+    auto& table = *table_opt.value();
+    for (const auto& existing_idx : table.indexes) {
+        if (existing_idx.name == index_name) {
+            throw std::runtime_error("Index already exists: " + index_name);
+        }
+    }
+
     IndexInfo index;
     index.index_id = next_oid_++;
     index.name = index_name;
@@ -148,7 +160,7 @@ oid_t Catalog::create_index(const std::string& index_name, oid_t table_id,
     index.is_unique = is_unique;
 
     const oid_t id = index.index_id;
-    (*table_opt)->indexes.push_back(std::move(index));
+    table.indexes.push_back(std::move(index));
     return id;
 }