Refactor test

Signed-off-by: Vijayan Balasubramanian <[email protected]>

src/main/java/org/opensearch/knn/index/query/KNNWeight.java

@@ -5,6 +5,7 @@
 
 package org.opensearch.knn.index.query;
 
+import com.google.common.annotations.VisibleForTesting;
 import lombok.extern.log4j.Log4j2;
 import org.apache.lucene.index.FieldInfo;
 import org.apache.lucene.index.LeafReaderContext;
@@ -95,8 +96,13 @@ public KNNWeight(KNNQuery query, float boost, Weight filterWeight) {
     }
 
     public static void initialize(ModelDao modelDao) {
+        initialize(modelDao, new ExactSearcher(modelDao));
+    }
+
+    @VisibleForTesting
+    static void initialize(ModelDao modelDao, ExactSearcher exactSearcher) {
         KNNWeight.modelDao = modelDao;
-        KNNWeight.DEFAULT_EXACT_SEARCHER = new ExactSearcher(modelDao);
+        KNNWeight.DEFAULT_EXACT_SEARCHER = exactSearcher;
     }
 
     @Override

src/test/java/org/opensearch/knn/index/query/KNNWeightTests.java

@@ -89,6 +89,7 @@
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.mockStatic;
 import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
 import static org.opensearch.knn.KNNRestTestCase.INDEX_NAME;
 import static org.opensearch.knn.common.KNNConstants.INDEX_DESCRIPTION_PARAMETER;
@@ -762,6 +763,83 @@ public void validateANNWithFilterQuery_whenExactSearch_thenSuccess(final boolean
         }
     }
 
+    @SneakyThrows
+    public void testRadialSearch_whenNoEngineFiles_thenPerformExactSearch() {
+        ExactSearcher mockedExactSearcher = mock(ExactSearcher.class);
+        final float[] queryVector = new float[] { 0.1f, 2.0f, 3.0f };
+        final SpaceType spaceType = randomFrom(SpaceType.L2, SpaceType.INNER_PRODUCT);
+        KNNWeight.initialize(null, mockedExactSearcher);
+        final KNNQuery query = KNNQuery.builder()
+            .field(FIELD_NAME)
+            .queryVector(queryVector)
+            .indexName(INDEX_NAME)
+            .methodParameters(HNSW_METHOD_PARAMETERS)
+            .build();
+        final KNNWeight knnWeight = new KNNWeight(query, 1.0f);
+
+        final LeafReaderContext leafReaderContext = mock(LeafReaderContext.class);
+        final SegmentReader reader = mock(SegmentReader.class);
+        when(leafReaderContext.reader()).thenReturn(reader);
+
+        final FSDirectory directory = mock(FSDirectory.class);
+        when(reader.directory()).thenReturn(directory);
+        final SegmentInfo segmentInfo = new SegmentInfo(
+            directory,
+            Version.LATEST,
+            Version.LATEST,
+            SEGMENT_NAME,
+            100,
+            false,
+            false,
+            KNNCodecVersion.current().getDefaultCodecDelegate(),
+            Map.of(),
+            new byte[StringHelper.ID_LENGTH],
+            Map.of(),
+            Sort.RELEVANCE
+        );
+        segmentInfo.setFiles(Set.of());
+        final SegmentCommitInfo segmentCommitInfo = new SegmentCommitInfo(segmentInfo, 0, 0, 0, 0, 0, new byte[StringHelper.ID_LENGTH]);
+        when(reader.getSegmentInfo()).thenReturn(segmentCommitInfo);
+
+        final Path path = mock(Path.class);
+        when(directory.getDirectory()).thenReturn(path);
+        final FieldInfos fieldInfos = mock(FieldInfos.class);
+        final FieldInfo fieldInfo = mock(FieldInfo.class);
+        when(reader.getFieldInfos()).thenReturn(fieldInfos);
+        when(fieldInfos.fieldInfo(FIELD_NAME)).thenReturn(fieldInfo);
+        when(fieldInfo.attributes()).thenReturn(
+            Map.of(
+                SPACE_TYPE,
+                spaceType.getValue(),
+                KNN_ENGINE,
+                KNNEngine.FAISS.getName(),
+                PARAMETERS,
+                String.format(Locale.ROOT, "{\"%s\":\"%s\"}", INDEX_DESCRIPTION_PARAMETER, "HNSW32")
+            )
+        );
+        final ExactSearcher.ExactSearcherContext exactSearchContext = ExactSearcher.ExactSearcherContext.builder()
+            .isParentHits(true)
+            // setting to true, so that if quantization details are present we want to do search on the quantized
+            // vectors as this flow is used in first pass of search.
+            .useQuantizedVectorsForSearch(true)
+            .knnQuery(query)
+            .build();
+        when(mockedExactSearcher.searchLeaf(leafReaderContext, exactSearchContext)).thenReturn(DOC_ID_TO_SCORES);
+        final KNNScorer knnScorer = (KNNScorer) knnWeight.scorer(leafReaderContext);
+        assertNotNull(knnScorer);
+        final DocIdSetIterator docIdSetIterator = knnScorer.iterator();
+        final List<Integer> actualDocIds = new ArrayList<>();
+        for (int docId = docIdSetIterator.nextDoc(); docId != NO_MORE_DOCS; docId = docIdSetIterator.nextDoc()) {
+            actualDocIds.add(docId);
+            assertEquals(DOC_ID_TO_SCORES.get(docId), knnScorer.score(), 0.00000001f);
+        }
+        assertEquals(docIdSetIterator.cost(), actualDocIds.size());
+        assertTrue(Comparators.isInOrder(actualDocIds, Comparator.naturalOrder()));
+        // verify JNI Service is not called
+        jniServiceMockedStatic.verifyNoInteractions();
+        verify(mockedExactSearcher).searchLeaf(leafReaderContext, exactSearchContext);
+    }
+
     @SneakyThrows
     public void testANNWithFilterQuery_whenExactSearchAndThresholdComputations_thenSuccess() {
         ModelDao modelDao = mock(ModelDao.class);