fix wildcard term & terms query & add YAML REST test

Author: gesong.samuel

rest-api-spec/src/main/resources/rest-api-spec/test/search/270_wildcard_fieldtype_queries.yml

@@ -227,3 +227,13 @@ setup:
               my_field:
                 value: ".*"
   - match: { hits.total.value: 5 }
+  ---
+"terms query on wildcard field matches":
+  - do:
+      search:
+        index: test
+        body:
+          query:
+            terms: { my_field: ["AbCd"] }
+  - match: { hits.total.value: 1 }
+  - match: { hits.hits.0._id: "5" }

server/src/main/java/org/opensearch/index/mapper/WildcardFieldMapper.java

@@ -635,7 +635,7 @@ public Query rangeQuery(Object lowerTerm, Object upperTerm, boolean includeLower
 
         @Override
         public Query termQueryCaseInsensitive(Object value, QueryShardContext context) {
-            return wildcardQuery(value.toString(), MultiTermQuery.CONSTANT_SCORE_REWRITE, true, context);
+            return wildcardQuery(BytesRefs.toString(value), MultiTermQuery.CONSTANT_SCORE_REWRITE, true, context);
         }
 
         @Override
@@ -649,7 +649,7 @@ public Query termsQuery(List<?> values, QueryShardContext context) {
             Set<String> expectedValues = new HashSet<>();
             StringBuilder pattern = new StringBuilder();
             for (Object value : values) {
-                String stringVal = value.toString();
+                String stringVal = BytesRefs.toString(value);
                 builder.add(matchAllTermsQuery(name(), getRequiredNGrams(stringVal)), BooleanClause.Occur.SHOULD);
                 expectedValues.add(stringVal);
                 if (pattern.length() > 0) {