[Tests] Adding tests for AvgAggregator

Relates to #22278

Author: cbuescher

core/src/test/java/org/elasticsearch/search/aggregations/metrics/avg/AvgAggregatorTests.java

@@ -0,0 +1,125 @@
+/*
+ * 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.avg;
+
+import org.apache.lucene.document.IntPoint;
+import org.apache.lucene.document.NumericDocValuesField;
+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.FieldValueQuery;
+import org.apache.lucene.search.IndexSearcher;
+import org.apache.lucene.search.MatchAllDocsQuery;
+import org.apache.lucene.search.Query;
+import org.apache.lucene.store.Directory;
+import org.elasticsearch.common.CheckedConsumer;
+import org.elasticsearch.index.mapper.MappedFieldType;
+import org.elasticsearch.index.mapper.NumberFieldMapper;
+import org.elasticsearch.search.aggregations.AggregatorTestCase;
+
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.function.Consumer;
+
+import static java.util.Collections.singleton;
+
+public class AvgAggregatorTests extends AggregatorTestCase {
+
+    public void testNoDocs() throws IOException {
+        testCase(new MatchAllDocsQuery(), iw -> {
+            // Intentionally not writing any docs
+        }, avg -> {
+            assertEquals(Double.NaN, avg.getValue(), 0);
+        });
+    }
+
+    public void testNoMatchingField() throws IOException {
+        testCase(new MatchAllDocsQuery(), iw -> {
+            iw.addDocument(singleton(new SortedNumericDocValuesField("wrong_number", 7)));
+            iw.addDocument(singleton(new SortedNumericDocValuesField("wrong_number", 3)));
+        }, avg -> {
+            assertEquals(Double.NaN, avg.getValue(), 0);
+        });
+    }
+
+    public void testSomeMatchesSortedNumericDocValues() throws IOException {
+        testCase(new FieldValueQuery("number"), iw -> {
+            iw.addDocument(singleton(new SortedNumericDocValuesField("number", 7)));
+            iw.addDocument(singleton(new SortedNumericDocValuesField("number", 2)));
+            iw.addDocument(singleton(new SortedNumericDocValuesField("number", 3)));
+        }, avg -> {
+            assertEquals(4, avg.getValue(), 0);
+        });
+    }
+
+    public void testSomeMatchesNumericDocValues() throws IOException {
+        testCase(new FieldValueQuery("number"), iw -> {
+            iw.addDocument(singleton(new NumericDocValuesField("number", 7)));
+            iw.addDocument(singleton(new NumericDocValuesField("number", 2)));
+            iw.addDocument(singleton(new NumericDocValuesField("number", 3)));
+        }, avg -> {
+            assertEquals(4, avg.getValue(), 0);
+        });
+    }
+
+    public void testQueryFiltering() throws IOException {
+        testCase(IntPoint.newRangeQuery("number", 0, 3), iw -> {
+            iw.addDocument(Arrays.asList(new IntPoint("number", 7), new SortedNumericDocValuesField("number", 7)));
+            iw.addDocument(Arrays.asList(new IntPoint("number", 1), new SortedNumericDocValuesField("number", 2)));
+            iw.addDocument(Arrays.asList(new IntPoint("number", 3), new SortedNumericDocValuesField("number", 3)));
+        }, avg -> {
+            assertEquals(2.5, avg.getValue(), 0);
+        });
+    }
+
+    public void testQueryFiltersAll() throws IOException {
+        testCase(IntPoint.newRangeQuery("number", -1, 0), iw -> {
+            iw.addDocument(Arrays.asList(new IntPoint("number", 7), new SortedNumericDocValuesField("number", 7)));
+            iw.addDocument(Arrays.asList(new IntPoint("number", 1), new SortedNumericDocValuesField("number", 2)));
+            iw.addDocument(Arrays.asList(new IntPoint("number", 3), new SortedNumericDocValuesField("number", 7)));
+        }, avg -> {
+            assertEquals(Double.NaN, avg.getValue(), 0);
+        });
+    }
+
+    private void testCase(Query query, CheckedConsumer<RandomIndexWriter, IOException> buildIndex, Consumer<InternalAvg> verify)
+            throws IOException {
+        Directory directory = newDirectory();
+        RandomIndexWriter indexWriter = new RandomIndexWriter(random(), directory);
+        buildIndex.accept(indexWriter);
+        indexWriter.close();
+
+        IndexReader indexReader = DirectoryReader.open(directory);
+        IndexSearcher indexSearcher = newSearcher(indexReader, true, true);
+
+        AvgAggregationBuilder aggregationBuilder = new AvgAggregationBuilder("_name").field("number");
+        MappedFieldType fieldType = new NumberFieldMapper.NumberFieldType(NumberFieldMapper.NumberType.LONG);
+        fieldType.setName("number");
+        try (AvgAggregator aggregator = createAggregator(aggregationBuilder, indexSearcher, fieldType)) {
+            aggregator.preCollection();
+            indexSearcher.search(query, aggregator);
+            aggregator.postCollection();
+            verify.accept((InternalAvg) aggregator.buildAggregation(0L));
+        }
+        indexReader.close();
+        directory.close();
+    }
+}