test: replaced integration tests with unit test

core/src/main/java/org/elasticsearch/index/query/HasChildQueryBuilder.java

@@ -355,6 +355,10 @@ public class HasChildQueryBuilder extends AbstractQueryBuilder<HasChildQueryBuil
         public Query getInnerQuery() {
             return innerQuery;
         }
+
+        public Similarity getSimilarity() {
+            return similarity;
+        }
     }
 
     @Override

core/src/test/java/org/elasticsearch/index/query/HasChildQueryBuilderTests.java

@@ -28,17 +28,22 @@ import org.apache.lucene.search.ConstantScoreQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.TermQuery;
 import org.apache.lucene.search.join.ScoreMode;
+import org.apache.lucene.search.similarities.DFISimilarity;
+import org.apache.lucene.search.similarities.PerFieldSimilarityWrapper;
+import org.apache.lucene.search.similarities.Similarity;
 import org.apache.lucene.util.BytesRef;
 import org.elasticsearch.ElasticsearchParseException;
 import org.elasticsearch.action.admin.indices.mapping.put.PutMappingRequest;
 import org.elasticsearch.common.ParsingException;
 import org.elasticsearch.common.compress.CompressedXContent;
+import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.index.fielddata.IndexFieldDataService;
 import org.elasticsearch.index.mapper.MapperService;
 import org.elasticsearch.index.mapper.Uid;
 import org.elasticsearch.index.mapper.internal.TypeFieldMapper;
 import org.elasticsearch.index.mapper.internal.UidFieldMapper;
 import org.elasticsearch.index.query.support.QueryInnerHits;
+import org.elasticsearch.index.similarity.SimilarityService;
 import org.elasticsearch.script.Script.ScriptParseException;
 import org.elasticsearch.search.fetch.innerhits.InnerHitsBuilder;
 import org.elasticsearch.search.fetch.innerhits.InnerHitsContext;
@@ -48,6 +53,7 @@ import org.elasticsearch.test.TestSearchContext;
 import org.junit.BeforeClass;
 
 import java.io.IOException;
+import java.util.ArrayList;
 import java.util.Collections;
 
 import static org.hamcrest.CoreMatchers.equalTo;
@@ -58,8 +64,11 @@ public class HasChildQueryBuilderTests extends AbstractQueryTestCase<HasChildQue
     protected static final String PARENT_TYPE = "parent";
     protected static final String CHILD_TYPE = "child";
 
+    private static String similarity;
+
     @BeforeClass
     public static void before() throws Exception {
+        similarity = randomFrom("classic", "BM25");
         MapperService mapperService = queryShardContext().getMapperService();
         mapperService.merge(PARENT_TYPE, new CompressedXContent(PutMappingRequest.buildFromSimplifiedDef(PARENT_TYPE,
                 STRING_FIELD_NAME, "type=text",
@@ -72,6 +81,7 @@ public class HasChildQueryBuilderTests extends AbstractQueryTestCase<HasChildQue
         mapperService.merge(CHILD_TYPE, new CompressedXContent(PutMappingRequest.buildFromSimplifiedDef(CHILD_TYPE,
                 "_parent", "type=" + PARENT_TYPE,
                 STRING_FIELD_NAME, "type=text",
+                "custom_string", "type=text,similarity=" + similarity,
                 INT_FIELD_NAME, "type=integer",
                 DOUBLE_FIELD_NAME, "type=double",
                 BOOLEAN_FIELD_NAME, "type=boolean",
@@ -300,4 +310,12 @@ public class HasChildQueryBuilderTests extends AbstractQueryTestCase<HasChildQue
             }
         }
     }
+
+    public void testNonDefaultSimilarity() throws Exception {
+        QueryShardContext shardContext = createShardContext();
+        HasChildQueryBuilder hasChildQueryBuilder = new HasChildQueryBuilder(CHILD_TYPE, new TermQueryBuilder("custom_string", "value"));
+        HasChildQueryBuilder.LateParsingQuery query = (HasChildQueryBuilder.LateParsingQuery) hasChildQueryBuilder.toQuery(shardContext);
+        Similarity expected = SimilarityService.BUILT_IN.get(similarity).apply(similarity, Settings.EMPTY).get();
+        assertThat(((PerFieldSimilarityWrapper) query.getSimilarity()).get("custom_string"), instanceOf(expected.getClass()));
+    }
 }

core/src/test/java/org/elasticsearch/search/child/ChildQuerySearchIT.java

@@ -1927,51 +1927,4 @@ public class ChildQuerySearchIT extends ESIntegTestCase {
                 QueryBuilders.hasChildQuery("child-type", new IdsQueryBuilder().addIds("child-id"))).get();
         assertSearchHits(searchResponse, "parent-id");
     }
-
-    // Tests #16550
-    public void testHasChildWithNonDefaultGlobalSimilarity() {
-      assertAcked(prepareCreate("test").setSettings(settingsBuilder().put(indexSettings())
-          .put("index.similarity.default.type", "BM25"))
-          .addMapping("parent")
-          .addMapping("child", "_parent", "type=parent", "c_field", "type=string"));
-      ensureGreen();
-
-      verifyNonDefaultSimilarity();
-    }
-
-    // Tests #16550
-    public void testHasChildWithNonDefaultFieldSimilarity() {
-      assertAcked(prepareCreate("test")
-          .addMapping("parent")
-          .addMapping("child", "_parent", "type=parent", "c_field", "type=string,similarity=BM25"));
-      ensureGreen();
-
-      verifyNonDefaultSimilarity();
-    }
-
-    // Tests #16550
-    private void verifyNonDefaultSimilarity() {
-      client().prepareIndex("test", "parent", "p1").setSource("p_field", "p_value1").get();
-      client().prepareIndex("test", "child", "c1").setSource("c_field", "c_value").setParent("p1").get();
-      client().prepareIndex("test", "child", "c2").setSource("c_field", "c_value").setParent("p1").get();
-      refresh();
-
-      // baseline: sum of scores of matching child docs outside of has_child query
-      SearchResponse searchResponse = client().prepareSearch("test")
-          .setTypes("child")
-          .setQuery(matchQuery("c_field", "c_value"))
-          .get();
-      assertSearchHits(searchResponse, "c1", "c2");
-      Float childSum = (float) Arrays.asList(searchResponse.getHits().getHits())
-          .stream()
-          .mapToDouble(hit -> hit.getScore())
-          .sum();
-
-      // compare baseline to has_child with 'total' score_mode
-      searchResponse = client().prepareSearch("test")
-          .setQuery(hasChildQuery("child", matchQuery("c_field", "c_value")).scoreMode(ScoreMode.Total))
-          .get();
-      assertSearchHits(searchResponse, "p1");
-      assertThat(searchResponse.getHits().hits()[0].score(), equalTo(childSum));
-    }
 }