Add test for *Builders helpers

Author: swallez

java-client/src/test/java/co/elastic/clients/elasticsearch/model/VariantsTest.java

@@ -21,6 +21,7 @@
 
 import co.elastic.clients.elasticsearch._types.mapping.Property;
 import co.elastic.clients.elasticsearch._types.query_dsl.Query;
+import co.elastic.clients.elasticsearch._types.query_dsl.QueryBuilders;
 import org.junit.Test;
 
 public class VariantsTest extends ModelTestCase {
@@ -93,4 +94,11 @@ public void testInternalTag() {
 
  assertTrue(property.ip().fields().get("a-field").float_().coerce());
  }
+
+ @Test
+ public void testBuilders() {
+ Query q = new Query(QueryBuilders.exists().field("foo"));
+
+ assertEquals("{\"exists\":{\"field\":\"foo\"}}", toJson(q));
+ }
 }