added tests for code coverage

Signed-off-by: Anthony Leong <aj.leong623@gmail.com>

Author: ajleong623

server/src/internalClusterTest/java/org/opensearch/search/sort/GeoDistanceSortBuilderIT.java

@@ -42,6 +42,7 @@
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.DistanceUnit;
 import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.index.query.BoolQueryBuilder;
 import org.opensearch.index.query.GeoValidationMethod;
 import org.opensearch.search.builder.SearchSourceBuilder;
 import org.opensearch.test.ParameterizedStaticSettingsOpenSearchIntegTestCase;
@@ -56,6 +57,8 @@
 import java.util.concurrent.ExecutionException;
 
 import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.opensearch.index.query.QueryBuilders.boolQuery;
+import static org.opensearch.index.query.QueryBuilders.existsQuery;
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
 import static org.opensearch.search.SearchService.CLUSTER_CONCURRENT_SEGMENT_SEARCH_SETTING;
 import static org.opensearch.search.sort.SortBuilders.fieldSort;
@@ -430,4 +433,38 @@ public void testCrossIndexIgnoreUnmapped() throws Exception {
             new Object[] { Double.POSITIVE_INFINITY, Double.NEGATIVE_INFINITY }
         );
     }
+
+    public void testGeoDistanceQueryThenSort() throws Exception {
+        assertAcked(prepareCreate("index").setMapping("admin", "type=keyword", LOCATION_FIELD, "type=geo_point"));
+
+        indexRandom(
+            true,
+            client().prepareIndex("index")
+                .setId("d1")
+                .setSource(
+                    jsonBuilder().startObject()
+                        .startObject(LOCATION_FIELD)
+                        .field("lat", 48.8331)
+                        .field("lon", 2.3264)
+                        .endObject()
+                        .field("admin", "11")
+                        .endObject()
+                )
+        );
+
+        GeoDistanceSortBuilder geoDistanceSortBuilder = new GeoDistanceSortBuilder(LOCATION_FIELD, new GeoPoint(40.7128, -74.0060));
+
+        BoolQueryBuilder bool = boolQuery().filter(existsQuery(LOCATION_FIELD));
+
+        SearchResponse searchResponse = client().prepareSearch()
+            .setQuery(bool)
+            .addSort(geoDistanceSortBuilder.unit(DistanceUnit.KILOMETERS).ignoreUnmapped(true).order(SortOrder.DESC))
+            .setSize(4)
+            .get();
+        assertOrderedSearchHits(searchResponse, "d1");
+        assertThat(
+            (Double) searchResponse.getHits().getAt(0).getSortValues()[0],
+            closeTo(GeoDistance.ARC.calculate(40.7128, -74.0060, 48.8331, 2.3264, DistanceUnit.KILOMETERS), 1.e-1)
+        );
+    }
 }