1 files changed, 197 insertions, 0 deletions
diff --git a/packages/server/src/core/logger.test.ts b/packages/server/src/core/logger.test.ts
new file mode 100644
index 00000000..9b4f4555
--- /dev/null
+++ b/packages/server/src/core/logger.test.ts
@@ -0,0 +1,197 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
+import { Logger, MessageSenderType } from './logger.js';
+
+// Mocks
+const mockDb = {
+  exec: vi.fn((_sql, callback) => callback?.(null)),
+  all: vi.fn((_sql, _params, callback) => callback?.(null, [])),
+  run: vi.fn((_sql, _params, callback) => callback?.(null)),
+  close: vi.fn((callback) => callback?.(null)),
+};
+
+vi.mock('sqlite3', () => ({
+  Database: vi.fn((_dbPath, _options, callback) => {
+    process.nextTick(() => callback?.(null));
+    return mockDb;
+  }),
+  default: {
+    Database: vi.fn((_dbPath, _options, callback) => {
+      process.nextTick(() => callback?.(null));
+      return mockDb;
+    }),
+  },
+}));
+
+describe('Logger', () => {
+  let logger: Logger;
+
+  beforeEach(async () => {
+    vi.resetAllMocks();
+
+    // Get a new instance for each test to ensure isolation,
+    logger = new Logger();
+    // We need to wait for the async initialize to complete
+    await logger.initialize().catch((err) => {
+      console.error('Error initializing logger:', err);
+    });
+  });
+
+  afterEach(() => {
+    vi.restoreAllMocks();
+    logger.close(); // Close the database connection after each test
+  });
+
+  describe('initialize', () => {
+    it('should execute create tables if not exists', async () => {
+      expect(mockDb.exec).toHaveBeenCalledWith(
+        expect.stringMatching(/CREATE TABLE IF NOT EXISTS messages/),
+        expect.any(Function),
+      );
+    });
+
+    it('should be idempotent', async () => {
+      mockDb.exec.mockClear();
+
+      await logger.initialize(); // Second call
+
+      expect(mockDb.exec).not.toHaveBeenCalled();
+    });
+  });
+
+  describe('logMessage', () => {
+    it('should insert a message into the database', async () => {
+      const type = MessageSenderType.USER;
+      const message = 'Hello, world!';
+      await logger.logMessage(type, message);
+      expect(mockDb.run).toHaveBeenCalledWith(
+        "INSERT INTO messages (session_id, message_id, type, message, timestamp) VALUES (?, ?, ?, ?, datetime('now'))",
+        [expect.any(Number), 0, type, message], // sessionId, messageId, type, message
+        expect.any(Function),
+      );
+    });
+
+    it('should increment messageId for subsequent messages', async () => {
+      await logger.logMessage(MessageSenderType.USER, 'First message');
+      expect(mockDb.run).toHaveBeenCalledWith(
+        expect.any(String),
+        [expect.any(Number), 0, MessageSenderType.USER, 'First message'],
+        expect.any(Function),
+      );
+      await logger.logMessage(MessageSenderType.USER, 'Second message');
+      expect(mockDb.run).toHaveBeenCalledWith(
+        expect.any(String),
+        [expect.any(Number), 1, MessageSenderType.USER, 'Second message'], // messageId is now 1
+        expect.any(Function),
+      );
+    });
+
+    it('should handle database not initialized', async () => {
+      const uninitializedLogger = new Logger();
+      // uninitializedLogger.initialize() is not called
+      const consoleErrorSpy = vi
+        .spyOn(console, 'error')
+        .mockImplementation(() => {});
+
+      await uninitializedLogger.logMessage(MessageSenderType.USER, 'test');
+
+      expect(consoleErrorSpy).toHaveBeenCalledWith('Database not initialized.');
+      expect(mockDb.run).not.toHaveBeenCalled();
+      consoleErrorSpy.mockRestore();
+    });
+
+    it('should handle error during db.run', async () => {
+      const error = new Error('db.run failed');
+      mockDb.run.mockImplementationOnce(
+        // eslint-disable-next-line @typescript-eslint/no-explicit-any
+        (_sql: any, _params: any, callback: any) => callback?.(error),
+      );
+
+      await expect(
+        logger.logMessage(MessageSenderType.USER, 'test'),
+      ).rejects.toThrow('db.run failed');
+    });
+  });
+
+  describe('getPreviousUserMessages', () => {
+    it('should query the database for messages', async () => {
+      mockDb.all.mockImplementationOnce(
+        // eslint-disable-next-line @typescript-eslint/no-explicit-any
+        (_sql: any, params: any, callback: any) =>
+          callback?.(null, [{ message: 'msg1' }, { message: 'msg2' }]),
+      );
+
+      const messages = await logger.getPreviousUserMessages();
+
+      expect(mockDb.all).toHaveBeenCalledWith(
+        expect.stringMatching(/SELECT message FROM messages/),
+        [],
+        expect.any(Function),
+      );
+      expect(messages).toEqual(['msg1', 'msg2']);
+    });
+
+    it('should handle database not initialized', async () => {
+      const uninitializedLogger = new Logger();
+      // uninitializedLogger.initialize() is not called
+      const consoleErrorSpy = vi
+        .spyOn(console, 'error')
+        .mockImplementation(() => {});
+
+      const messages = await uninitializedLogger.getPreviousUserMessages();
+
+      expect(consoleErrorSpy).toHaveBeenCalledWith('Database not initialized.');
+      expect(messages).toEqual([]);
+      expect(mockDb.all).not.toHaveBeenCalled();
+      consoleErrorSpy.mockRestore();
+    });
+
+    it('should handle error during db.all', async () => {
+      const error = new Error('db.all failed');
+      mockDb.all.mockImplementationOnce(
+        // eslint-disable-next-line @typescript-eslint/no-explicit-any
+        (_sql: any, _params: any, callback: any) => callback?.(error, []),
+      );
+
+      await expect(logger.getPreviousUserMessages()).rejects.toThrow(
+        'db.all failed',
+      );
+    });
+  });
+
+  describe('close', () => {
+    it('should close the database connection', () => {
+      logger.close();
+      expect(mockDb.close).toHaveBeenCalled();
+    });
+
+    it('should handle database not initialized', () => {
+      const uninitializedLogger = new Logger();
+      // uninitializedLogger.initialize() is not called
+      uninitializedLogger.close();
+      expect(() => uninitializedLogger.close()).not.toThrow();
+    });
+
+    it('should handle error during db.close', () => {
+      const error = new Error('db.close failed');
+      mockDb.close.mockImplementationOnce((callback: (error: Error) => void) =>
+        callback?.(error),
+      );
+      const consoleErrorSpy = vi
+        .spyOn(console, 'error')
+        .mockImplementation(() => {});
+
+      logger.close();
+      expect(consoleErrorSpy).toHaveBeenCalledWith(
+        'Error closing database:',
+        error.message,
+      );
+      consoleErrorSpy.mockRestore();
+    });
+  });
+});