fix(admin): clarify invalid group name errors (#5986)

crates/e2e_test/src/group_delete_test.rs

@@ -14,7 +14,7 @@
 
 //! E2E tests for group management (fixes #2028).
 
-use crate::common::{RustFSTestEnvironment, awscurl_delete, awscurl_get, awscurl_put, init_logging};
+use crate::common::{RustFSTestEnvironment, admin_request, awscurl_delete, awscurl_get, awscurl_put, init_logging};
 use aws_sdk_s3::config::{Credentials, Region};
 use aws_sdk_s3::{Client, Config};
 use serial_test::serial;
@@ -32,6 +32,56 @@ fn create_user_s3_client(env: &RustFSTestEnvironment, access_key: &str, secret_k
     Client::from_conf(config)
 }
 
+#[tokio::test(flavor = "multi_thread")]
+async fn update_group_members_rejects_invalid_new_group_names() -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
+    init_logging();
+
+    let mut env = RustFSTestEnvironment::new().await?;
+    env.start_rustfs_server(vec![]).await?;
+
+    let invalid_groups = [
+        ("test group", "group name contains whitespace"),
+        ("test=group", "group name contains reserved characters =,"),
+        ("test,group", "group name contains reserved characters =,"),
+    ];
+
+    for (group, expected_message) in invalid_groups {
+        let body = serde_json::json!({
+            "group": group,
+            "members": [],
+            "isRemove": false,
+            "groupStatus": "enabled"
+        })
+        .to_string();
+        let (status, response_body) = admin_request(
+            &env.url,
+            http::Method::PUT,
+            "/rustfs/admin/v3/update-group-members",
+            Some(body),
+            &env.access_key,
+            &env.secret_key,
+        )
+        .await?;
+
+        assert_eq!(
+            status,
+            reqwest::StatusCode::BAD_REQUEST,
+            "invalid group {group:?} must return HTTP 400, body: {response_body}"
+        );
+        assert!(
+            response_body.contains("<Code>InvalidArgument</Code>"),
+            "invalid group {group:?} must return InvalidArgument, body: {response_body}"
+        );
+        assert!(
+            response_body.contains(&format!("<Message>{expected_message}</Message>")),
+            "invalid group {group:?} returned an unexpected message: {response_body}"
+        );
+    }
+
+    env.stop_server();
+    Ok(())
+}
+
 /// Test that deleting a group with members fails, and deleting an empty group succeeds.
 #[tokio::test(flavor = "multi_thread")]
 #[serial]