Add comprehensive database testing suite with CI/CD integration

.env.test

@@ -0,0 +1,21 @@
+# Database Test Environment Configuration
+# ========================================
+# This file is used by VS Code when running tests
+# Copy and modify as needed for your local setup
+
+# SQLite In-Memory (Default - No Setup Required)
+# Use this for quick local testing without external dependencies
+TEST_DATABASE_URL=sqlite+aiosqlite:///:memory:
+TEST_SYNC_DATABASE_URL=sqlite:///:memory:
+
+# PostgreSQL via Docker
+# Uncomment these lines if you want to test with PostgreSQL
+# First start the container: docker run -d --name nerdlearn-test-db -e POSTGRES_USER=test -e POSTGRES_PASSWORD=test -e POSTGRES_DB=nerdlearn_test -p 5433:5432 postgres:15
+# TEST_DATABASE_URL=postgresql+asyncpg://test:test@localhost:5433/nerdlearn_test
+# TEST_SYNC_DATABASE_URL=postgresql://test:test@localhost:5433/nerdlearn_test
+
+# Logging
+LOG_LEVEL=WARNING
+
+# Test Configuration
+PYTEST_TIMEOUT=60