implemented 0.db as admin database architecture + updated test file

tests/redis_tests.rs

@@ -23,18 +23,29 @@ async fn start_test_server(test_name: &str) -> (Server, u16) {
         encrypt: false,
         encryption_key: None,
         backend: herodb::options::BackendType::Redb,
+        admin_secret: "test-admin".to_string(),
     };
     
     let server = Server::new(option).await;
     (server, port)
 }
 
-// Helper function to connect to the test server
+ // Helper function to connect to the test server
 async fn connect_to_server(port: u16) -> TcpStream {
     let mut attempts = 0;
     loop {
         match TcpStream::connect(format!("127.0.0.1:{}", port)).await {
-            Ok(stream) => return stream,
+            Ok(mut stream) => {
+                // Obtain ReadWrite permissions for this connection by selecting DB 0 with admin key
+                let resp = send_command(
+                    &mut stream,
+                    "*4\r\n$6\r\nSELECT\r\n$1\r\n0\r\n$3\r\nKEY\r\n$10\r\ntest-admin\r\n",
+                ).await;
+                if !resp.contains("OK") {
+                    panic!("Failed to acquire write permissions via SELECT 0 KEY test-admin: {}", resp);
+                }
+                return stream;
+            }
             Err(_) if attempts < 10 => {
                 attempts += 1;
                 sleep(Duration::from_millis(100)).await;