Improve Test Coverage to >85%

CMakeLists.txt

@@ -84,6 +84,9 @@ endmacro()
 # Tests
 if(BUILD_TESTS)
     enable_testing()
+    add_cloudsql_test(catalog_coverage_tests tests/catalog_coverage_tests.cpp)
+    add_cloudsql_test(transaction_coverage_tests tests/transaction_coverage_tests.cpp)
+    add_cloudsql_test(utils_coverage_tests tests/utils_coverage_tests.cpp)
     add_cloudsql_test(cloudSQL_tests tests/cloudSQL_tests.cpp)
     add_cloudsql_test(server_tests tests/server_tests.cpp)
     add_cloudsql_test(statement_tests tests/statement_tests.cpp)

tests/catalog_coverage_tests.cpp

@@ -0,0 +1,158 @@
+/**
+ * @file catalog_coverage_tests.cpp
+ * @brief Targeted unit tests to increase coverage of the Catalog module
+ */
+
+#include <gtest/gtest.h>
+
+#include <cstring>
+#include <vector>
+
+#include "catalog/catalog.hpp"
+#include "common/value.hpp"
+#include "distributed/raft_types.hpp"
+
+using namespace cloudsql;
+
+namespace {
+
+/**
+ * @brief Tests Catalog behavior with missing entities and invalid lookups.
+ */
+TEST(CatalogCoverageTests, MissingEntities) {
+    auto catalog = Catalog::create();
+
+    // Invalid table lookup
+    EXPECT_FALSE(catalog->get_table(9999).has_value());
+    EXPECT_FALSE(catalog->table_exists(9999));
+    EXPECT_FALSE(catalog->table_exists_by_name("non_existent"));
+    EXPECT_FALSE(catalog->get_table_by_name("non_existent").has_value());
+
+    // Invalid index lookup
+    EXPECT_FALSE(catalog->get_index(8888).has_value());
+    EXPECT_TRUE(catalog->get_table_indexes(9999).empty());
+
+    // Dropping non-existent entities
+    EXPECT_FALSE(catalog->drop_table(9999));
+    EXPECT_FALSE(catalog->drop_index(8888));
+
+    // Update stats for non-existent table
+    EXPECT_FALSE(catalog->update_table_stats(9999, 100));
+}
+
+/**
+ * @brief Tests Catalog behavior with duplicate entities and creation edge cases.
+ */
+TEST(CatalogCoverageTests, DuplicateEntities) {
+    auto catalog = Catalog::create();
+    std::vector<ColumnInfo> cols = {{"id", common::ValueType::TYPE_INT64, 0}};
+
+    oid_t tid = catalog->create_table("test_table", cols);
+    ASSERT_NE(tid, 0);
+
+    // Duplicate table creation should throw
+    EXPECT_THROW(catalog->create_table("test_table", cols), std::runtime_error);
+
+    // Create an index
+    oid_t iid = catalog->create_index("idx_id", tid, {0}, IndexType::BTree, true);
+    ASSERT_NE(iid, 0);
+
+    // Duplicate index creation should throw
+    EXPECT_THROW(catalog->create_index("idx_id", tid, {0}, IndexType::BTree, true),
+                 std::runtime_error);
+
+    // Creating index on missing table
+    EXPECT_EQ(catalog->create_index("idx_missing", 9999, {0}, IndexType::BTree, false), 0);
+}
+
+/**
+ * @brief Helper to serialize CreateTable command for Raft simulation
+ */
+std::vector<uint8_t> serialize_create_table(const std::string& name,
+                                            const std::vector<ColumnInfo>& columns) {
+    std::vector<uint8_t> data;
+    data.push_back(1);  // Type 1
+
+    uint32_t name_len = name.size();
+    size_t off = data.size();
+    data.resize(off + 4 + name_len);
+    std::memcpy(data.data() + off, &name_len, 4);
+    std::memcpy(data.data() + off + 4, name.data(), name_len);
+
+    uint32_t col_count = columns.size();
+    off = data.size();
+    data.resize(off + 4);
+    std::memcpy(data.data() + off, &col_count, 4);
+
+    for (const auto& col : columns) {
+        uint32_t cname_len = col.name.size();
+        off = data.size();
+        data.resize(off + 4 + cname_len + 1 + 2);
+        std::memcpy(data.data() + off, &cname_len, 4);
+        std::memcpy(data.data() + off + 4, col.name.data(), cname_len);
+        data[off + 4 + cname_len] = static_cast<uint8_t>(col.type);
+        std::memcpy(data.data() + off + 4 + cname_len + 1, &col.position, 2);
+    }
+
+    uint32_t shard_count = 1;
+    off = data.size();
+    data.resize(off + 4);
+    std::memcpy(data.data() + off, &shard_count, 4);
+
+    std::string addr = "127.0.0.1";
+    uint32_t addr_len = addr.size();
+    uint32_t sid = 0;
+    uint16_t port = 6441;
+
+    off = data.size();
+    data.resize(off + 4 + addr_len + 4 + 2);
+    std::memcpy(data.data() + off, &addr_len, 4);
+    std::memcpy(data.data() + off + 4, addr.data(), addr_len);
+    std::memcpy(data.data() + off + 4 + addr_len, &sid, 4);
+    std::memcpy(data.data() + off + 4 + addr_len + 4, &port, 2);
+
+    return data;
+}
+
+/**
+ * @brief Tests the Raft state machine application (apply) in the Catalog.
+ */
+TEST(CatalogCoverageTests, RaftApply) {
+    auto catalog = Catalog::create();
+
+    // 1. Replay CreateTable
+    std::vector<ColumnInfo> cols = {{"id", common::ValueType::TYPE_INT64, 0}};
+    std::vector<uint8_t> create_data = serialize_create_table("raft_table", cols);
+
+    raft::LogEntry entry;
+    entry.term = 1;
+    entry.index = 1;
+    entry.data = create_data;
+
+    catalog->apply(entry);
+    EXPECT_TRUE(catalog->table_exists_by_name("raft_table"));
+
+    auto table_opt = catalog->get_table_by_name("raft_table");
+    ASSERT_TRUE(table_opt.has_value());
+    oid_t tid = (*table_opt)->table_id;
+
+    // 2. Replay DropTable
+    std::vector<uint8_t> drop_data;
+    drop_data.push_back(2);  // Type 2
+    drop_data.resize(5);
+    std::memcpy(drop_data.data() + 1, &tid, 4);
+
+    entry.index = 2;
+    entry.data = drop_data;
+
+    catalog->apply(entry);
+    EXPECT_FALSE(catalog->table_exists(tid));
+    EXPECT_FALSE(catalog->table_exists_by_name("raft_table"));
+
+    // 3. Replay with empty data (should do nothing)
+    entry.index = 3;
+    entry.data.clear();
+    catalog->apply(entry);
+}
+
+}  // namespace

tests/transaction_coverage_tests.cpp

@@ -0,0 +1,137 @@
+/**
+ * @file transaction_coverage_tests.cpp
+ * @brief Targeted unit tests to increase coverage of Transaction and Lock Manager
+ */
+
+#include <gtest/gtest.h>
+
+#include <atomic>
+#include <chrono>
+#include <thread>
+#include <vector>
+
+#include "catalog/catalog.hpp"
+#include "common/config.hpp"
+#include "storage/buffer_pool_manager.hpp"
+#include "storage/heap_table.hpp"
+#include "storage/storage_manager.hpp"
+#include "transaction/lock_manager.hpp"
+#include "transaction/transaction.hpp"
+#include "transaction/transaction_manager.hpp"
+
+using namespace cloudsql;
+using namespace cloudsql::transaction;
+using namespace cloudsql::storage;
+
+namespace {
+
+/**
+ * @brief Stress tests the LockManager with concurrent shared and exclusive requests.
+ */
+TEST(TransactionCoverageTests, LockManagerConcurrency) {
+    LockManager lm;
+    const int num_readers = 5;
+    std::vector<std::thread> readers;
+    std::atomic<int> shared_granted{0};
+    std::atomic<bool> stop{false};
+
+    Transaction writer_txn(100);
+
+    // Writers holds exclusive lock initially
+    ASSERT_TRUE(lm.acquire_exclusive(&writer_txn, "RESOURCE"));
+
+    for (int i = 0; i < num_readers; ++i) {
+        readers.emplace_back([&, i]() {
+            Transaction reader_txn(i);
+            if (lm.acquire_shared(&reader_txn, "RESOURCE")) {
+                shared_granted++;
+                while (!stop) {
+                    std::this_thread::yield();
+                }
+                lm.unlock(&reader_txn, "RESOURCE");
+            }
+        });
+    }
+
+    // Readers should be blocked by the writer
+    std::this_thread::sleep_for(std::chrono::milliseconds(200));
+    EXPECT_EQ(shared_granted.load(), 0);
+
+    // Release writer lock, readers should proceed
+    lm.unlock(&writer_txn, "RESOURCE");
+
+    // Wait for all readers to get the lock
+    for (int i = 0; i < 50 && shared_granted.load() < num_readers; ++i) {
+        std::this_thread::sleep_for(std::chrono::milliseconds(50));
+    }
+    EXPECT_EQ(shared_granted.load(), num_readers);
+
+    stop = true;
+    for (auto& t : readers) {
+        t.join();
+    }
+}
+
+/**
+ * @brief Tests deep rollback functionality via the Undo Log.
+ */
+TEST(TransactionCoverageTests, DeepRollback) {
+    auto catalog = Catalog::create();
+    StorageManager disk_manager("./test_data");
+    BufferPoolManager bpm(config::Config::DEFAULT_BUFFER_POOL_SIZE, disk_manager);
+    LockManager lm;
+    TransactionManager tm(lm, *catalog, bpm, nullptr);
+
+    std::vector<ColumnInfo> cols = {{"id", common::ValueType::TYPE_INT64, 0},
+                                    {"val", common::ValueType::TYPE_TEXT, 1}};
+    oid_t tid = catalog->create_table("rollback_stress", cols);
+
+    executor::Schema schema;
+    schema.add_column("id", common::ValueType::TYPE_INT64);
+    schema.add_column("val", common::ValueType::TYPE_TEXT);
+
+    HeapTable table("rollback_stress", bpm, schema);
+    table.create();
+
+    Transaction* txn = tm.begin();
+
+    // 1. Insert some data
+    auto rid1 =
+        table.insert(executor::Tuple({common::Value::make_int64(1), common::Value::make_text("A")}),
+                     txn->get_id());
+    txn->add_undo_log(UndoLog::Type::INSERT, "rollback_stress", rid1);
+
+    auto rid2 =
+        table.insert(executor::Tuple({common::Value::make_int64(2), common::Value::make_text("B")}),
+                     txn->get_id());
+    txn->add_undo_log(UndoLog::Type::INSERT, "rollback_stress", rid2);
+
+    // 2. Update data
+    table.remove(rid1, txn->get_id());  // Mark old version deleted
+    auto rid1_new = table.insert(
+        executor::Tuple({common::Value::make_int64(1), common::Value::make_text("A_NEW")}),
+        txn->get_id());
+    txn->add_undo_log(UndoLog::Type::UPDATE, "rollback_stress", rid1_new, rid1);
+
+    // 3. Delete data
+    table.remove(rid2, txn->get_id());
+    txn->add_undo_log(UndoLog::Type::DELETE, "rollback_stress", rid2);
+
+    EXPECT_EQ(table.tuple_count(), 1U);  // rid1_new is active, rid1 and rid2 are logically deleted
+
+    // 4. Abort
+    tm.abort(txn);
+
+    // 5. Verify restoration
+    EXPECT_EQ(table.tuple_count(),
+              0U);  // Inserted rows should be physically removed or logically invisible
+
+    // The table should be empty because we aborted the inserts
+    auto iter = table.scan();
+    executor::Tuple t;
+    EXPECT_FALSE(iter.next(t));
+
+    static_cast<void>(std::remove("./test_data/rollback_stress.heap"));
+}
+
+}  // namespace