Share testing random exponential histogram generation across modules (elastic#136590)

Author: JonasKunz

libs/exponential-histogram/src/test/java/org/elasticsearch/exponentialhistogram/ExponentialHistogramEqualityTests.java

@@ -59,7 +59,8 @@ public ExponentialHistogramEqualityTests(Modification modification) {
     }
 
     public void testEquality() {
-        ExponentialHistogram histo = randomHistogram();
+        ReleasableExponentialHistogram histo = ExponentialHistogramTestUtils.randomHistogram(breaker());
+        autoReleaseOnTestEnd(histo);
         ReleasableExponentialHistogram copy = ExponentialHistogram.builder(histo, breaker()).build();
         autoReleaseOnTestEnd(copy);
         ExponentialHistogram modifiedCopy = copyWithModification(histo, modification);
@@ -70,7 +71,8 @@ public void testEquality() {
     }
 
     public void testHashQuality() {
-        ExponentialHistogram histo = randomHistogram();
+        ReleasableExponentialHistogram histo = ExponentialHistogramTestUtils.randomHistogram(breaker());
+        autoReleaseOnTestEnd(histo);
         // of 10 tries, at least one should produce a different hash code
         for (int i = 0; i < 10; i++) {
             ExponentialHistogram modifiedCopy = copyWithModification(histo, modification);
@@ -81,10 +83,6 @@ public void testHashQuality() {
         fail("Could not produce different hash code after 10 tries");
     }
 
-    private ExponentialHistogram randomHistogram() {
-        return createAutoReleasedHistogram(randomIntBetween(4, 20), randomDoubles(randomIntBetween(0, 200)).toArray());
-    }
-
     private ExponentialHistogram copyWithModification(ExponentialHistogram toCopy, Modification modification) {
         ExponentialHistogramBuilder copyBuilder = ExponentialHistogram.builder(toCopy, breaker());
         switch (modification) {

libs/exponential-histogram/src/test/java/org/elasticsearch/exponentialhistogram/ExponentialHistogramTestUtils.java

@@ -0,0 +1,63 @@
+/*
+ * Copyright Elasticsearch B.V., and/or licensed to Elasticsearch B.V.
+ * under one or more license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. 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.
+ *
+ * This file is based on a modification of https://github.com/open-telemetry/opentelemetry-java which is licensed under the Apache 2.0 License.
+ */
+
+package org.elasticsearch.exponentialhistogram;
+
+import java.util.stream.DoubleStream;
+import java.util.stream.IntStream;
+
+import static org.elasticsearch.test.ESTestCase.randomBoolean;
+import static org.elasticsearch.test.ESTestCase.randomDouble;
+import static org.elasticsearch.test.ESTestCase.randomIntBetween;
+
+public abstract class ExponentialHistogramTestUtils {
+
+    public static ExponentialHistogram randomHistogram() {
+        return randomHistogram(ExponentialHistogramCircuitBreaker.noop());
+    }
+
+    public static ReleasableExponentialHistogram randomHistogram(ExponentialHistogramCircuitBreaker breaker) {
+        boolean hasNegativeValues = randomBoolean();
+        boolean hasPositiveValues = randomBoolean();
+        boolean hasZeroValues = randomBoolean();
+        double[] rawValues = IntStream.concat(
+            IntStream.concat(
+                hasNegativeValues ? IntStream.range(0, randomIntBetween(1, 1000)).map(i1 -> -1) : IntStream.empty(),
+                hasPositiveValues ? IntStream.range(0, randomIntBetween(1, 1000)).map(i1 -> 1) : IntStream.empty()
+            ),
+            hasZeroValues ? IntStream.range(0, randomIntBetween(1, 100)).map(i1 -> 0) : IntStream.empty()
+        ).mapToDouble(sign -> sign * (Math.pow(1_000_000, randomDouble()))).toArray();
+
+        int numBuckets = randomIntBetween(4, 300);
+        ReleasableExponentialHistogram histo = ExponentialHistogram.create(numBuckets, breaker, rawValues);
+        // Setup a proper zeroThreshold based on a random chance
+        if (histo.zeroBucket().count() > 0 && randomBoolean()) {
+            double smallestNonZeroValue = DoubleStream.of(rawValues).map(Math::abs).filter(val -> val != 0).min().orElse(0.0);
+            double zeroThreshold = smallestNonZeroValue * randomDouble();
+            try (ReleasableExponentialHistogram releaseAfterCopy = histo) {
+                histo = ExponentialHistogram.builder(histo, breaker)
+                    .zeroBucket(ZeroBucket.create(zeroThreshold, histo.zeroBucket().count()))
+                    .build();
+            }
+        }
+        return histo;
+    }
+}

x-pack/plugin/mapper-exponential-histogram/build.gradle

@@ -26,6 +26,7 @@ restResources {
 dependencies {
   api project(":libs:exponential-histogram")
   compileOnly project(path: xpackModule('core'))
+  testImplementation(testArtifact(project(":libs:exponential-histogram")))
   yamlRestTestImplementation(testArtifact(project(xpackModule('core'))))
 }
 

x-pack/plugin/mapper-exponential-histogram/src/test/java/org/elasticsearch/xpack/exponentialhistogram/aggregations/metrics/ExponentialHistogramAggregatorTestCase.java

@@ -10,8 +10,7 @@
 import org.apache.lucene.index.IndexableField;
 import org.apache.lucene.tests.index.RandomIndexWriter;
 import org.elasticsearch.exponentialhistogram.ExponentialHistogram;
-import org.elasticsearch.exponentialhistogram.ExponentialHistogramBuilder;
-import org.elasticsearch.exponentialhistogram.ExponentialHistogramCircuitBreaker;
+import org.elasticsearch.exponentialhistogram.ExponentialHistogramTestUtils;
 import org.elasticsearch.plugins.SearchPlugin;
 import org.elasticsearch.search.aggregations.AggregatorTestCase;
 import org.elasticsearch.xpack.exponentialhistogram.ExponentialHistogramFieldMapper;
@@ -32,30 +31,7 @@ protected List<SearchPlugin> getSearchPlugins() {
     }
 
     protected static List<ExponentialHistogram> createRandomHistograms(int count) {
-        return IntStream.range(0, count).mapToObj(i -> {
-            boolean hasNegativeValues = randomBoolean();
-            boolean hasPositiveValues = randomBoolean();
-            boolean hasZeroValues = randomBoolean();
-            double[] rawValues = IntStream.concat(
-                IntStream.concat(
-                    hasNegativeValues ? IntStream.range(0, randomIntBetween(1, 1000)).map(i1 -> -1) : IntStream.empty(),
-                    hasPositiveValues ? IntStream.range(0, randomIntBetween(1, 1000)).map(i1 -> 1) : IntStream.empty()
-                ),
-                hasZeroValues ? IntStream.range(0, randomIntBetween(1, 100)).map(i1 -> 0) : IntStream.empty()
-            ).mapToDouble(sign -> sign * (Math.pow(1_000_000, randomDouble()))).toArray();
-
-            int numBuckets = randomIntBetween(4, 300);
-            ExponentialHistogram histo = ExponentialHistogram.create(numBuckets, ExponentialHistogramCircuitBreaker.noop(), rawValues);
-            // Randomize sum, min and max a little
-            if (histo.valueCount() > 0) {
-                ExponentialHistogramBuilder builder = ExponentialHistogram.builder(histo, ExponentialHistogramCircuitBreaker.noop());
-                builder.sum(histo.sum() + (randomDouble() - 0.5) * 10_000);
-                builder.max(histo.max() - randomDouble());
-                builder.min(histo.min() + randomDouble());
-                histo = builder.build();
-            }
-            return histo;
-        }).toList();
+        return IntStream.range(0, count).mapToObj(i -> ExponentialHistogramTestUtils.randomHistogram()).toList();
     }
 
     protected static void addHistogramDoc(