Add comprehensive test suite for image processing and related services

- Implement tests for database generator to ensure proper session handling.
- Create tests for EXIF extraction and conversion functions.
- Add tests for image-related endpoints, ensuring proper data retrieval and isolation between clients.
- Develop tests for OCR functionality, including language detection and text extraction.
- Introduce tests for the image processing pipeline, covering success and failure scenarios.
- Validate rate limiting functionality and ensure independent counters for different clients.
- Implement scraper tests to verify HTML content fetching and error handling.
- Add unit tests for various services, including storage and filename generation.
- Establish worker entry point for ARQ to handle background image processing tasks.

tests/test_database_extended.py

@@ -0,0 +1,45 @@
+import pytest
+import hashlib
+from sqlalchemy import select
+from app.database import init_db
+from app.models.client import APIClient
+from unittest.mock import patch, MagicMock
+
+@pytest.mark.asyncio
+async def test_init_db_creates_default_client():
+    # Mock engine and AsyncSessionLocal
+    with patch("app.database.engine") as mock_engine, \
+         patch("app.database.AsyncSessionLocal") as mock_session_factory:
+        
+        # Mock engine.begin() context manager
+        mock_conn = AsyncMock()
+        mock_engine.begin.return_value.__aenter__.return_value = mock_conn
+        
+        # Mock session behavior
+        mock_session = AsyncMockSession()
+        mock_session_factory.return_value.__aenter__.return_value = mock_session
+        
+        # Simulate empty table
+        mock_result = MagicMock()
+        mock_result.scalar_one_or_none.return_value = None
+        mock_session.execute.return_value = mock_result
+        
+        await init_db()
+        
+        # Check if add was called for bootstrap client
+        assert any(isinstance(call.args[0], APIClient) for call in mock_session.add.call_args_list)
+
+class AsyncMockSession:
+    def __init__(self):
+        self.add = MagicMock()
+        self.commit = AsyncMock()
+        self.execute = AsyncMock()
+        self.close = AsyncMock()
+    async def __aenter__(self): return self
+    async def __aexit__(self, *args): pass
+
+class AsyncMock(MagicMock):
+    async def __call__(self, *args, **kwargs):
+        return super(AsyncMock, self).__call__(*args, **kwargs)
+    def __await__(self):
+        return self().__await__()