Added integration test and fixed the code style issues

Author: mridula-s109

x-pack/plugin/search-business-rules/src/main/java/org/elasticsearch/xpack/searchbusinessrules/retriever/PinnedRetrieverBuilder.java

@@ -118,9 +118,9 @@ public int rankWindowSize() {
      * @return a PinnedQueryBuilder or the original query if no pinned documents
      */
     private QueryBuilder createPinnedQuery(QueryBuilder baseQuery) {
-        if (!docs.isEmpty()) {
+        if (docs.isEmpty() == false) {
             return new PinnedQueryBuilder(baseQuery, docs.toArray(new SpecifiedDocument[0]));
-        } else if (!ids.isEmpty()) {
+        } else if (ids.isEmpty() == false) {
             return new PinnedQueryBuilder(baseQuery, ids.toArray(new String[0]));
         } else {
             return baseQuery;
@@ -135,10 +135,10 @@ protected SearchSourceBuilder finalizeSourceBuilder(SearchSourceBuilder source)
 
     @Override
     public void doToXContent(XContentBuilder builder, Params params) throws IOException {
-        if (ids != null && !ids.isEmpty()) {
+        if (ids != null && ids.isEmpty() == false) {
             builder.array(IDS_FIELD.getPreferredName(), ids.toArray());
         }
-        if (docs != null && !docs.isEmpty()) {
+        if (docs != null && docs.isEmpty() == false) {
             builder.startArray(DOCS_FIELD.getPreferredName());
             for (SpecifiedDocument doc : docs) {
                 builder.value(doc);

x-pack/plugin/search-business-rules/src/test/java/org/elasticsearch/xpack/searchbusinessrules/retriever/PinnedRetrieverBuilderTests.java

@@ -36,7 +36,7 @@ public class PinnedRetrieverBuilderTests extends AbstractXContentTestCase<Pinned
 
     public static PinnedRetrieverBuilder createRandomPinnedRetrieverBuilder() {
         boolean useIds = randomBoolean();
-        boolean useDocs = !useIds || randomBoolean();
+        boolean useDocs = useIds == false || randomBoolean();
 
         List<String> ids = useIds ? List.of(randomAlphaOfLengthBetween(5, 10), randomAlphaOfLengthBetween(5, 10)) : new ArrayList<>();
         List<SpecifiedDocument> docs = useDocs
@@ -47,6 +47,14 @@ public static PinnedRetrieverBuilder createRandomPinnedRetrieverBuilder() {
             : new ArrayList<>();
 
         return new PinnedRetrieverBuilder(ids, docs, TestRetrieverBuilder.createRandomTestRetrieverBuilder(), randomIntBetween(1, 100));
+        List<SpecifiedDocument> docs = useDocs
+            ? List.of(
+                new SpecifiedDocument(randomAlphaOfLengthBetween(5, 10), randomAlphaOfLengthBetween(5, 10)),
+                new SpecifiedDocument(randomAlphaOfLengthBetween(5, 10), randomAlphaOfLengthBetween(5, 10))
+            )
+            : new ArrayList<>();
+
+        return new PinnedRetrieverBuilder(ids, docs, TestRetrieverBuilder.createRandomTestRetrieverBuilder(), randomIntBetween(1, 100));
     }
 
     @Override
@@ -59,6 +67,7 @@ protected PinnedRetrieverBuilder doParseInstance(XContentParser parser) throws I
         return (PinnedRetrieverBuilder) RetrieverBuilder.parseTopLevelRetrieverBuilder(
             parser,
             new RetrieverParserContext(new SearchUsage(), nf -> true)
+            new RetrieverParserContext(new SearchUsage(), nf -> true)
         );
     }
 
@@ -70,6 +79,7 @@ protected boolean supportsUnknownFields() {
     @Override
     protected String[] getShuffleFieldsExceptions() {
         return new String[] { PinnedRetrieverBuilder.IDS_FIELD.getPreferredName(), PinnedRetrieverBuilder.DOCS_FIELD.getPreferredName() };
+        return new String[] { PinnedRetrieverBuilder.IDS_FIELD.getPreferredName(), PinnedRetrieverBuilder.DOCS_FIELD.getPreferredName() };
     }
 
     @Override
@@ -159,3 +169,5 @@ public void testPinnedRetrieverParsing() throws IOException {
         }
     }
 }
+
+}