Tests: Add unit test for InternalScriptedMetricAggregator (#23404)

Relates to #22278

core/src/main/java/org/elasticsearch/search/aggregations/metrics/scripted/ScriptedMetricAggregationBuilder.java

@@ -190,7 +190,7 @@ protected ScriptedMetricAggregatorFactory doBuild(SearchContext context, Aggrega
         if (initScript != null) {
             executableInitScript = queryShardContext.getLazyExecutableScript(initScript, ScriptContext.Standard.AGGS);
         } else {
-            executableInitScript = (p) -> null;;
+            executableInitScript = (p) -> null;
         }
         Function<Map<String, Object>, SearchScript> searchMapScript = queryShardContext.getLazySearchScript(mapScript,
             ScriptContext.Standard.AGGS);

core/src/test/java/org/elasticsearch/search/aggregations/AggregatorTestCase.java

@@ -125,13 +125,8 @@ public boolean shouldCache(Query query) throws IOException {
         SearchLookup searchLookup = new SearchLookup(mapperService, ifds, new String[]{"type"});
         when(searchContext.lookup()).thenReturn(searchLookup);
 
-        QueryShardContext queryShardContext = mock(QueryShardContext.class);
-        for (MappedFieldType fieldType : fieldTypes) {
-            when(queryShardContext.fieldMapper(fieldType.name())).thenReturn(fieldType);
-            when(queryShardContext.getForField(fieldType)).then(invocation -> fieldType.fielddataBuilder().build(
-                    indexSettings, fieldType, new IndexFieldDataCache.None(), circuitBreakerService, mock(MapperService.class)));
-            when(searchContext.getQueryShardContext()).thenReturn(queryShardContext);
-        }
+        QueryShardContext queryShardContext = queryShardContextMock(fieldTypes, indexSettings, circuitBreakerService);
+        when(searchContext.getQueryShardContext()).thenReturn(queryShardContext);
 
         @SuppressWarnings("unchecked")
         A aggregator = (A) aggregationBuilder.build(searchContext, null).create(null, true);
@@ -145,6 +140,20 @@ protected MapperService mapperServiceMock() {
         return mock(MapperService.class);
     }
 
+    /**
+     * sub-tests that need a more complex mock can overwrite this
+     */
+    protected QueryShardContext queryShardContextMock(MappedFieldType[] fieldTypes, IndexSettings indexSettings,
+            CircuitBreakerService circuitBreakerService) {
+        QueryShardContext queryShardContext = mock(QueryShardContext.class);
+        for (MappedFieldType fieldType : fieldTypes) {
+            when(queryShardContext.fieldMapper(fieldType.name())).thenReturn(fieldType);
+            when(queryShardContext.getForField(fieldType)).then(invocation -> fieldType.fielddataBuilder().build(indexSettings, fieldType,
+                    new IndexFieldDataCache.None(), circuitBreakerService, mock(MapperService.class)));
+        }
+        return queryShardContext;
+    }
+
     protected <A extends InternalAggregation, C extends Aggregator> A search(IndexSearcher searcher,
                                                                              Query query,
                                                                              AggregationBuilder builder,

core/src/test/java/org/elasticsearch/search/aggregations/metrics/scripted/ScriptedMetricAggregatorTests.java

@@ -0,0 +1,171 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.elasticsearch.search.aggregations.metrics.scripted;
+
+import org.apache.lucene.document.SortedNumericDocValuesField;
+import org.apache.lucene.index.DirectoryReader;
+import org.apache.lucene.index.IndexReader;
+import org.apache.lucene.index.RandomIndexWriter;
+import org.apache.lucene.search.MatchAllDocsQuery;
+import org.apache.lucene.store.Directory;
+import org.elasticsearch.ElasticsearchException;
+import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.env.Environment;
+import org.elasticsearch.index.IndexSettings;
+import org.elasticsearch.index.mapper.MappedFieldType;
+import org.elasticsearch.index.query.QueryShardContext;
+import org.elasticsearch.indices.breaker.CircuitBreakerService;
+import org.elasticsearch.script.MockScriptEngine;
+import org.elasticsearch.script.Script;
+import org.elasticsearch.script.ScriptContextRegistry;
+import org.elasticsearch.script.ScriptEngineRegistry;
+import org.elasticsearch.script.ScriptService;
+import org.elasticsearch.script.ScriptSettings;
+import org.elasticsearch.script.ScriptType;
+import org.elasticsearch.search.aggregations.AggregatorTestCase;
+import org.junit.BeforeClass;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.function.Function;
+
+import static java.util.Collections.singleton;
+
+public class ScriptedMetricAggregatorTests extends AggregatorTestCase {
+
+    private static final String AGG_NAME = "scriptedMetric";
+    private static final Script INIT_SCRIPT = new Script(ScriptType.INLINE, MockScriptEngine.NAME, "initScript", Collections.emptyMap());
+    private static final Script MAP_SCRIPT = new Script(ScriptType.INLINE, MockScriptEngine.NAME, "mapScript", Collections.emptyMap());
+    private static final Script COMBINE_SCRIPT = new Script(ScriptType.INLINE, MockScriptEngine.NAME, "combineScript", Collections.emptyMap());
+    private static final Map<String, Function<Map<String, Object>, Object>> SCRIPTS = new HashMap<>();
+
+
+    @BeforeClass
+    @SuppressWarnings("unchecked")
+    public static void initMockScripts() {
+        SCRIPTS.put("initScript", params -> {
+            Map<String, Object> agg = (Map<String, Object>) params.get("_agg");
+            agg.put("collector", new ArrayList<Integer>());
+            return agg;
+            });
+        SCRIPTS.put("mapScript", params -> {
+            Map<String, Object> agg = (Map<String, Object>) params.get("_agg");
+            ((List<Integer>) agg.get("collector")).add(1); // just add 1 for each doc the script is run on
+            return agg;
+        });
+        SCRIPTS.put("combineScript", params -> {
+            Map<String, Object> agg = (Map<String, Object>) params.get("_agg");
+            return ((List<Integer>) agg.get("collector")).stream().mapToInt(Integer::intValue).sum();
+        });
+    }
+
+    @SuppressWarnings("unchecked")
+    public void testNoDocs() throws IOException {
+        try (Directory directory = newDirectory()) {
+            try (RandomIndexWriter indexWriter = new RandomIndexWriter(random(), directory)) {
+                // intentionally not writing any docs
+            }
+            try (IndexReader indexReader = DirectoryReader.open(directory)) {
+                ScriptedMetricAggregationBuilder aggregationBuilder = new ScriptedMetricAggregationBuilder(AGG_NAME);
+                aggregationBuilder.mapScript(MAP_SCRIPT); // map script is mandatory, even if its not used in this case
+                ScriptedMetric scriptedMetric = search(newSearcher(indexReader, true, true), new MatchAllDocsQuery(), aggregationBuilder);
+                assertEquals(AGG_NAME, scriptedMetric.getName());
+                assertNotNull(scriptedMetric.aggregation());
+                assertEquals(0, ((HashMap<Object, String>) scriptedMetric.aggregation()).size());
+            }
+        }
+    }
+
+    /**
+     * without combine script, the "_aggs" map should contain a list of the size of the number of documents matched
+     */
+    @SuppressWarnings("unchecked")
+    public void testScriptedMetricWithoutCombine() throws IOException {
+        try (Directory directory = newDirectory()) {
+            int numDocs = randomInt(100);
+            try (RandomIndexWriter indexWriter = new RandomIndexWriter(random(), directory)) {
+                for (int i = 0; i < numDocs; i++) {
+                    indexWriter.addDocument(singleton(new SortedNumericDocValuesField("number", i)));
+                }
+            }
+            try (IndexReader indexReader = DirectoryReader.open(directory)) {
+                ScriptedMetricAggregationBuilder aggregationBuilder = new ScriptedMetricAggregationBuilder(AGG_NAME);
+                aggregationBuilder.initScript(INIT_SCRIPT).mapScript(MAP_SCRIPT);
+                ScriptedMetric scriptedMetric = search(newSearcher(indexReader, true, true), new MatchAllDocsQuery(), aggregationBuilder);
+                assertEquals(AGG_NAME, scriptedMetric.getName());
+                assertNotNull(scriptedMetric.aggregation());
+                Map<String, Object> agg = (Map<String, Object>) scriptedMetric.aggregation();
+                assertEquals(numDocs, ((List<Integer>) agg.get("collector")).size());
+            }
+        }
+    }
+
+    /**
+     * test that combine script sums the list produced by the "mapScript"
+     */
+    public void testScriptedMetricWithCombine() throws IOException {
+        try (Directory directory = newDirectory()) {
+            Integer numDocs = randomInt(100);
+            try (RandomIndexWriter indexWriter = new RandomIndexWriter(random(), directory)) {
+                for (int i = 0; i < numDocs; i++) {
+                    indexWriter.addDocument(singleton(new SortedNumericDocValuesField("number", i)));
+                }
+            }
+            try (IndexReader indexReader = DirectoryReader.open(directory)) {
+                ScriptedMetricAggregationBuilder aggregationBuilder = new ScriptedMetricAggregationBuilder(AGG_NAME);
+                aggregationBuilder.initScript(INIT_SCRIPT).mapScript(MAP_SCRIPT).combineScript(COMBINE_SCRIPT);
+                ScriptedMetric scriptedMetric = search(newSearcher(indexReader, true, true), new MatchAllDocsQuery(), aggregationBuilder);
+                assertEquals(AGG_NAME, scriptedMetric.getName());
+                assertNotNull(scriptedMetric.aggregation());
+                assertEquals(numDocs, scriptedMetric.aggregation());
+            }
+        }
+    }
+
+    /**
+     * We cannot use Mockito for mocking QueryShardContext in this case because
+     * script-related methods (e.g. QueryShardContext#getLazyExecutableScript)
+     * is final and cannot be mocked
+     */
+    @Override
+    protected QueryShardContext queryShardContextMock(final MappedFieldType[] fieldTypes, IndexSettings idxSettings,
+            CircuitBreakerService circuitBreakerService) {
+        Settings settings = Settings.builder().put(Environment.PATH_HOME_SETTING.getKey(), createTempDir())
+                 // no file watching, so we don't need a ResourceWatcherService
+                .put(ScriptService.SCRIPT_AUTO_RELOAD_ENABLED_SETTING.getKey(), "false").build();
+        MockScriptEngine scriptEngine = new MockScriptEngine(MockScriptEngine.NAME, SCRIPTS);
+        ScriptEngineRegistry scriptEngineRegistry = new ScriptEngineRegistry(Collections.singletonList(scriptEngine));
+        ScriptContextRegistry scriptContextRegistry = new ScriptContextRegistry(Collections.emptyList());
+        ScriptSettings scriptSettings = new ScriptSettings(scriptEngineRegistry, scriptContextRegistry);
+        ScriptService scriptService;
+        try {
+            scriptService =  new ScriptService(settings, new Environment(settings), null, scriptEngineRegistry, scriptContextRegistry,
+                    scriptSettings);
+        } catch (IOException e) {
+            throw new ElasticsearchException(e);
+        }
+        return new QueryShardContext(0, idxSettings, null, null, null, null, scriptService, xContentRegistry(),
+                null, null, System::currentTimeMillis);
+    }
+}