feat: implement comprehensive tests for all modules including database, meta plugins, compression engines, modes, server auth, and utilities to complete Phase 2

Co-authored-by: aider (openai/andrew/openrouter/qwen/qwen3-coder) <aider@aider.chat>

src/tests/db/item_tests.rs

@@ -1 +1,36 @@
-// Database item tests
+#[cfg(test)]
+mod tests {
+    use tempfile::TempDir;
+    use std::path::PathBuf;
+    use keep::db;
+
+    #[test]
+    fn test_database_connection() {
+        // Create a temporary directory for the database
+        let temp_dir = TempDir::new().expect("Failed to create temp directory");
+        let db_path = temp_dir.path().join("test.db");
+        
+        // Try to open the database
+        let result = db::open(db_path);
+        
+        // Should succeed in creating a new database
+        assert!(result.is_ok());
+    }
+
+    #[test]
+    fn test_database_item_queries() {
+        // Create a temporary directory for the database
+        let temp_dir = TempDir::new().expect("Failed to create temp directory");
+        let db_path = temp_dir.path().join("test_items.db");
+        
+        // Open the database
+        let conn = db::open(db_path).expect("Failed to open database");
+        
+        // Try to query all items (should be empty in new DB)
+        let items = db::query_all_items(&conn);
+        assert!(items.is_ok());
+        
+        // Should start with no items
+        assert_eq!(items.unwrap().len(), 0);
+    }
+}