Add integration and unit tests for missing RRF coverage (#997)

* Initial unit test implementation

Signed-off-by: Ryan Bogan <rbogan@amazon.com>

---------
Signed-off-by: Ryan Bogan <rbogan@amazon.com>

src/main/java/org/opensearch/neuralsearch/processor/RRFProcessor.java

@@ -13,6 +13,7 @@
 import java.util.Optional;
 
 import lombok.Getter;
+import org.opensearch.ml.repackage.com.google.common.annotations.VisibleForTesting;
 import org.opensearch.neuralsearch.processor.combination.ScoreCombinationTechnique;
 import org.opensearch.neuralsearch.processor.normalization.ScoreNormalizationTechnique;
 import org.opensearch.search.fetch.FetchSearchResult;
@@ -98,7 +99,8 @@ public boolean isIgnoreFailure() {
         return false;
     }
 
-    private <Result extends SearchPhaseResult> boolean shouldSkipProcessor(SearchPhaseResults<Result> searchPhaseResult) {
+    @VisibleForTesting
+    <Result extends SearchPhaseResult> boolean shouldSkipProcessor(SearchPhaseResults<Result> searchPhaseResult) {
         if (Objects.isNull(searchPhaseResult) || !(searchPhaseResult instanceof QueryPhaseResultConsumer queryPhaseResultConsumer)) {
             return true;
         }
@@ -111,7 +113,8 @@ private <Result extends SearchPhaseResult> boolean shouldSkipProcessor(SearchPha
      * @param searchPhaseResult
      * @return true if results are from hybrid query
      */
-    private boolean isHybridQuery(final SearchPhaseResult searchPhaseResult) {
+    @VisibleForTesting
+    boolean isHybridQuery(final SearchPhaseResult searchPhaseResult) {
         // check for delimiter at the end of the score docs.
         return Objects.nonNull(searchPhaseResult.queryResult())
             && Objects.nonNull(searchPhaseResult.queryResult().topDocs())
@@ -120,17 +123,16 @@ private boolean isHybridQuery(final SearchPhaseResult searchPhaseResult) {
             && isHybridQueryStartStopElement(searchPhaseResult.queryResult().topDocs().topDocs.scoreDocs[0]);
     }
 
-    private <Result extends SearchPhaseResult> List<QuerySearchResult> getQueryPhaseSearchResults(
-        final SearchPhaseResults<Result> results
-    ) {
+    <Result extends SearchPhaseResult> List<QuerySearchResult> getQueryPhaseSearchResults(final SearchPhaseResults<Result> results) {
         return results.getAtomicArray()
             .asList()
             .stream()
             .map(result -> result == null ? null : result.queryResult())
             .collect(Collectors.toList());
     }
 
-    private <Result extends SearchPhaseResult> Optional<FetchSearchResult> getFetchSearchResults(
+    @VisibleForTesting
+    <Result extends SearchPhaseResult> Optional<FetchSearchResult> getFetchSearchResults(
         final SearchPhaseResults<Result> searchPhaseResults
     ) {
         Optional<Result> optionalFirstSearchPhaseResult = searchPhaseResults.getAtomicArray().asList().stream().findFirst();

src/test/java/org/opensearch/neuralsearch/processor/RRFProcessorIT.java

@@ -0,0 +1,93 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+package org.opensearch.neuralsearch.processor;
+
+import lombok.SneakyThrows;
+import org.opensearch.index.query.MatchQueryBuilder;
+import org.opensearch.knn.index.query.KNNQueryBuilder;
+import org.opensearch.neuralsearch.BaseNeuralSearchIT;
+import org.opensearch.neuralsearch.query.HybridQueryBuilder;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+
+import static org.opensearch.neuralsearch.util.TestUtils.DELTA_FOR_SCORE_ASSERTION;
+import static org.opensearch.neuralsearch.util.TestUtils.TEST_SPACE_TYPE;
+
+public class RRFProcessorIT extends BaseNeuralSearchIT {
+
+    private int currentDoc = 1;
+    private static final String RRF_INDEX_NAME = "rrf-index";
+    private static final String RRF_SEARCH_PIPELINE = "rrf-search-pipeline";
+    private static final String RRF_INGEST_PIPELINE = "rrf-ingest-pipeline";
+
+    private static final int RRF_DIMENSION = 5;
+
+    @SneakyThrows
+    public void testRRF_whenValidInput_thenSucceed() {
+        try {
+            createPipelineProcessor(null, RRF_INGEST_PIPELINE, ProcessorType.TEXT_EMBEDDING);
+            prepareKnnIndex(
+                RRF_INDEX_NAME,
+                Collections.singletonList(new KNNFieldConfig("passage_embedding", RRF_DIMENSION, TEST_SPACE_TYPE))
+            );
+            addDocuments();
+            createDefaultRRFSearchPipeline();
+
+            HybridQueryBuilder hybridQueryBuilder = getHybridQueryBuilder();
+
+            Map<String, Object> results = search(
+                RRF_INDEX_NAME,
+                hybridQueryBuilder,
+                null,
+                5,
+                Map.of("search_pipeline", RRF_SEARCH_PIPELINE)
+            );
+            Map<String, Object> hits = (Map<String, Object>) results.get("hits");
+            ArrayList<HashMap<String, Object>> hitsList = (ArrayList<HashMap<String, Object>>) hits.get("hits");
+            assertEquals(3, hitsList.size());
+            assertEquals(0.016393442, (Double) hitsList.getFirst().get("_score"), DELTA_FOR_SCORE_ASSERTION);
+            assertEquals(0.016129032, (Double) hitsList.get(1).get("_score"), DELTA_FOR_SCORE_ASSERTION);
+            assertEquals(0.015873017, (Double) hitsList.getLast().get("_score"), DELTA_FOR_SCORE_ASSERTION);
+        } finally {
+            wipeOfTestResources(RRF_INDEX_NAME, RRF_INGEST_PIPELINE, null, RRF_SEARCH_PIPELINE);
+        }
+    }
+
+    private HybridQueryBuilder getHybridQueryBuilder() {
+        MatchQueryBuilder matchQueryBuilder = new MatchQueryBuilder("text", "cowboy rodeo bronco");
+        KNNQueryBuilder knnQueryBuilder = new KNNQueryBuilder.Builder().fieldName("passage_embedding")
+            .k(5)
+            .vector(new float[] { 0.1f, 1.2f, 2.3f, 3.4f, 4.5f })
+            .build();
+
+        HybridQueryBuilder hybridQueryBuilder = new HybridQueryBuilder();
+        hybridQueryBuilder.add(matchQueryBuilder);
+        hybridQueryBuilder.add(knnQueryBuilder);
+        return hybridQueryBuilder;
+    }
+
+    @SneakyThrows
+    private void addDocuments() {
+        addDocument(
+            "A West Virginia university women 's basketball team , officials , and a small gathering of fans are in a West Virginia arena .",
+            "4319130149.jpg"
+        );
+        addDocument("A wild animal races across an uncut field with a minimal amount of trees .", "1775029934.jpg");
+        addDocument(
+            "People line the stands which advertise Freemont 's orthopedics , a cowboy rides a light brown bucking bronco .",
+            "2664027527.jpg"
+        );
+        addDocument("A man who is riding a wild horse in the rodeo is very near to falling off .", "4427058951.jpg");
+        addDocument("A rodeo cowboy , wearing a cowboy hat , is being thrown off of a wild white horse .", "2691147709.jpg");
+    }
+
+    @SneakyThrows
+    private void addDocument(String description, String imageText) {
+        addDocument(RRF_INDEX_NAME, String.valueOf(currentDoc++), "text", description, "image_text", imageText);
+    }
+}

src/test/java/org/opensearch/neuralsearch/processor/RRFProcessorTests.java

@@ -0,0 +1,226 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+package org.opensearch.neuralsearch.processor;
+
+import lombok.SneakyThrows;
+import org.apache.lucene.search.ScoreDoc;
+import org.apache.lucene.search.TopDocs;
+import org.apache.lucene.search.TotalHits;
+import org.junit.Before;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+import org.opensearch.action.OriginalIndices;
+import org.opensearch.action.search.QueryPhaseResultConsumer;
+import org.opensearch.action.search.SearchPhaseContext;
+import org.opensearch.action.search.SearchPhaseName;
+import org.opensearch.action.search.SearchPhaseResults;
+import org.opensearch.action.search.SearchRequest;
+import org.opensearch.action.support.IndicesOptions;
+import org.opensearch.common.lucene.search.TopDocsAndMaxScore;
+import org.opensearch.common.util.concurrent.AtomicArray;
+import org.opensearch.core.common.Strings;
+import org.opensearch.core.index.shard.ShardId;
+import org.opensearch.neuralsearch.processor.combination.ScoreCombinationTechnique;
+import org.opensearch.neuralsearch.processor.normalization.ScoreNormalizationTechnique;
+import org.opensearch.neuralsearch.search.util.HybridSearchResultFormatUtil;
+import org.opensearch.search.DocValueFormat;
+import org.opensearch.search.SearchPhaseResult;
+import org.opensearch.search.SearchShardTarget;
+import org.opensearch.search.builder.SearchSourceBuilder;
+import org.opensearch.search.fetch.FetchSearchResult;
+import org.opensearch.search.internal.AliasFilter;
+import org.opensearch.search.internal.ShardSearchContextId;
+import org.opensearch.search.internal.ShardSearchRequest;
+import org.opensearch.search.query.QuerySearchResult;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.util.List;
+import java.util.Optional;
+
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+public class RRFProcessorTests extends OpenSearchTestCase {
+
+    @Mock
+    private ScoreNormalizationTechnique mockNormalizationTechnique;
+    @Mock
+    private ScoreCombinationTechnique mockCombinationTechnique;
+    @Mock
+    private NormalizationProcessorWorkflow mockNormalizationWorkflow;
+    @Mock
+    private SearchPhaseResults<SearchPhaseResult> mockSearchPhaseResults;
+    @Mock
+    private SearchPhaseContext mockSearchPhaseContext;
+    @Mock
+    private QueryPhaseResultConsumer mockQueryPhaseResultConsumer;
+
+    private RRFProcessor rrfProcessor;
+    private static final String TAG = "tag";
+    private static final String DESCRIPTION = "description";
+
+    @Before
+    @SneakyThrows
+    public void setUp() {
+        super.setUp();
+        MockitoAnnotations.openMocks(this);
+        rrfProcessor = new RRFProcessor(TAG, DESCRIPTION, mockNormalizationTechnique, mockCombinationTechnique, mockNormalizationWorkflow);
+    }
+
+    @SneakyThrows
+    public void testGetType() {
+        assertEquals(RRFProcessor.TYPE, rrfProcessor.getType());
+    }
+
+    @SneakyThrows
+    public void testGetBeforePhase() {
+        assertEquals(SearchPhaseName.QUERY, rrfProcessor.getBeforePhase());
+    }
+
+    @SneakyThrows
+    public void testGetAfterPhase() {
+        assertEquals(SearchPhaseName.FETCH, rrfProcessor.getAfterPhase());
+    }
+
+    @SneakyThrows
+    public void testIsIgnoreFailure() {
+        assertFalse(rrfProcessor.isIgnoreFailure());
+    }
+
+    @SneakyThrows
+    public void testProcess_whenNullSearchPhaseResult_thenSkipWorkflow() {
+        rrfProcessor.process(null, mockSearchPhaseContext);
+        verify(mockNormalizationWorkflow, never()).execute(any());
+    }
+
+    @SneakyThrows
+    public void testProcess_whenNonQueryPhaseResultConsumer_thenSkipWorkflow() {
+        rrfProcessor.process(mockSearchPhaseResults, mockSearchPhaseContext);
+        verify(mockNormalizationWorkflow, never()).execute(any());
+    }
+
+    @SneakyThrows
+    public void testProcess_whenValidHybridInput_thenSucceed() {
+        QuerySearchResult result = createQuerySearchResult(true);
+        AtomicArray<SearchPhaseResult> atomicArray = new AtomicArray<>(1);
+        atomicArray.set(0, result);
+
+        when(mockQueryPhaseResultConsumer.getAtomicArray()).thenReturn(atomicArray);
+
+        rrfProcessor.process(mockQueryPhaseResultConsumer, mockSearchPhaseContext);
+
+        verify(mockNormalizationWorkflow).execute(any(NormalizationExecuteDTO.class));
+    }
+
+    @SneakyThrows
+    public void testProcess_whenValidNonHybridInput_thenSucceed() {
+        QuerySearchResult result = createQuerySearchResult(false);
+        AtomicArray<SearchPhaseResult> atomicArray = new AtomicArray<>(1);
+        atomicArray.set(0, result);
+
+        when(mockQueryPhaseResultConsumer.getAtomicArray()).thenReturn(atomicArray);
+
+        rrfProcessor.process(mockQueryPhaseResultConsumer, mockSearchPhaseContext);
+
+        verify(mockNormalizationWorkflow, never()).execute(any(NormalizationExecuteDTO.class));
+    }
+
+    @SneakyThrows
+    public void testGetTag() {
+        assertEquals(TAG, rrfProcessor.getTag());
+    }
+
+    @SneakyThrows
+    public void testGetDescription() {
+        assertEquals(DESCRIPTION, rrfProcessor.getDescription());
+    }
+
+    @SneakyThrows
+    public void testShouldSkipProcessor() {
+        assertTrue(rrfProcessor.shouldSkipProcessor(null));
+        assertTrue(rrfProcessor.shouldSkipProcessor(mockSearchPhaseResults));
+
+        AtomicArray<SearchPhaseResult> atomicArray = new AtomicArray<>(1);
+        atomicArray.set(0, createQuerySearchResult(false));
+        when(mockQueryPhaseResultConsumer.getAtomicArray()).thenReturn(atomicArray);
+
+        assertTrue(rrfProcessor.shouldSkipProcessor(mockQueryPhaseResultConsumer));
+
+        atomicArray.set(0, createQuerySearchResult(true));
+        assertFalse(rrfProcessor.shouldSkipProcessor(mockQueryPhaseResultConsumer));
+    }
+
+    @SneakyThrows
+    public void testGetQueryPhaseSearchResults() {
+        AtomicArray<SearchPhaseResult> atomicArray = new AtomicArray<>(2);
+        atomicArray.set(0, createQuerySearchResult(true));
+        atomicArray.set(1, createQuerySearchResult(false));
+        when(mockQueryPhaseResultConsumer.getAtomicArray()).thenReturn(atomicArray);
+
+        List<QuerySearchResult> results = rrfProcessor.getQueryPhaseSearchResults(mockQueryPhaseResultConsumer);
+        assertEquals(2, results.size());
+        assertNotNull(results.get(0));
+        assertNotNull(results.get(1));
+    }
+
+    @SneakyThrows
+    public void testGetFetchSearchResults() {
+        AtomicArray<SearchPhaseResult> atomicArray = new AtomicArray<>(1);
+        atomicArray.set(0, createQuerySearchResult(true));
+        when(mockQueryPhaseResultConsumer.getAtomicArray()).thenReturn(atomicArray);
+
+        Optional<FetchSearchResult> result = rrfProcessor.getFetchSearchResults(mockQueryPhaseResultConsumer);
+        assertFalse(result.isPresent());
+    }
+
+    private QuerySearchResult createQuerySearchResult(boolean isHybrid) {
+        ShardId shardId = new ShardId("index", "uuid", 0);
+        OriginalIndices originalIndices = new OriginalIndices(new String[] { "index" }, IndicesOptions.strictExpandOpenAndForbidClosed());
+        SearchRequest searchRequest = new SearchRequest("index");
+        searchRequest.source(new SearchSourceBuilder());
+        searchRequest.allowPartialSearchResults(true);
+
+        int numberOfShards = 1;
+        AliasFilter aliasFilter = new AliasFilter(null, Strings.EMPTY_ARRAY);
+        float indexBoost = 1.0f;
+        long nowInMillis = System.currentTimeMillis();
+        String clusterAlias = null;
+        String[] indexRoutings = Strings.EMPTY_ARRAY;
+
+        ShardSearchRequest shardSearchRequest = new ShardSearchRequest(
+            originalIndices,
+            searchRequest,
+            shardId,
+            numberOfShards,
+            aliasFilter,
+            indexBoost,
+            nowInMillis,
+            clusterAlias,
+            indexRoutings
+        );
+
+        QuerySearchResult result = new QuerySearchResult(
+            new ShardSearchContextId("test", 1),
+            new SearchShardTarget("node1", shardId, clusterAlias, originalIndices),
+            shardSearchRequest
+        );
+        result.from(0).size(10);
+
+        ScoreDoc[] scoreDocs;
+        if (isHybrid) {
+            scoreDocs = new ScoreDoc[] { HybridSearchResultFormatUtil.createStartStopElementForHybridSearchResults(0) };
+        } else {
+            scoreDocs = new ScoreDoc[] { new ScoreDoc(0, 1.0f) };
+        }
+
+        TopDocs topDocs = new TopDocs(new TotalHits(1, TotalHits.Relation.EQUAL_TO), scoreDocs);
+        TopDocsAndMaxScore topDocsAndMaxScore = new TopDocsAndMaxScore(topDocs, 1.0f);
+        result.topDocs(topDocsAndMaxScore, new DocValueFormat[0]);
+
+        return result;
+    }
+}