Add a test to make sure we throw the right error message

milli/tests/search/mod.rs

@@ -13,6 +13,7 @@ use slice_group_by::GroupBy;
 mod distinct;
 mod filters;
 mod query_criteria;
+mod sort;
 
 pub const TEST_QUERY: &'static str = "hello world america";
 

milli/tests/search/sort.rs

@@ -0,0 +1,23 @@
+use big_s::S;
+use milli::Criterion::{Attribute, Exactness, Proximity, Typo, Words};
+use milli::{AscDesc, Error, Search, UserError};
+
+use crate::search::{self, EXTERNAL_DOCUMENTS_IDS};
+
+#[test]
+fn sort_ranking_rule_missing() {
+    let criteria = vec![Words, Typo, Proximity, Attribute, Exactness];
+    // sortables: `tag` and `asc_desc_rank`
+    let index = search::setup_search_index_with_criteria(&criteria);
+    let rtxn = index.read_txn().unwrap();
+
+    let mut search = Search::new(&rtxn, &index);
+    search.query(search::TEST_QUERY);
+    search.limit(EXTERNAL_DOCUMENTS_IDS.len());
+    search.authorize_typos(true);
+    search.optional_words(true);
+    search.sort_criteria(vec![AscDesc::Asc(S("tag"))]);
+
+    let result = search.execute();
+    assert!(matches!(result, Err(Error::UserError(UserError::SortRankingRuleMissing))));
+}