Check setting in tests

Author: thecoop

server/src/internalClusterTest/java/org/elasticsearch/index/store/DirectIOIT.java

@@ -72,7 +72,7 @@ protected Collection<Class<? extends Plugin>> nodePlugins() {
     }
 
     private void indexVectors() {
-        String type = randomFrom(/*"bbq_flat", */"bbq_hnsw");
+        String type = "bbq_hnsw";
         assertAcked(
             prepareCreate("foo-vectors").setSettings(Settings.builder().put(InternalSettingsPlugin.USE_COMPOUND_FILE.getKey(), false))
                 .setMapping("""
@@ -102,11 +102,12 @@ private void indexVectors() {
         assertBBQIndexType(type); // test assertion to ensure that the correct index type is being used
     }
 
-    @SuppressWarnings("unchecked")
     static void assertBBQIndexType(String type) {
         var response = indicesAdmin().prepareGetFieldMappings("foo-vectors").setFields("fooVector").get();
-        var map = (Map<String, Object>) response.fieldMappings("foo-vectors", "fooVector").sourceAsMap().get("fooVector");
-        assertThat((String) ((Map<String, Object>) map.get("index_options")).get("type"), is(equalTo(type)));
+        var map = (Map<?, ?>) response.fieldMappings("foo-vectors", "fooVector").sourceAsMap().get("fooVector");
+        var options = (Map<?, ?>) map.get("index_options");
+        assertThat(options.get("type"), is(equalTo(type)));
+        assertThat(options.get("disable_offheap_cache_rescoring"), is(true));
     }
 
     @TestLogging(value = "org.elasticsearch.index.store.FsDirectoryFactory:DEBUG", reason = "to capture trace logging for direct IO")