[incubator-paimon] branch master updated: [core] Add test for histogram metric (#1618)

[cz...@apache.org]

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czweng pushed a commit to branch master
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The following commit(s) were added to refs/heads/master by this push:
     new 95a7407e0 [core] Add test for histogram metric (#1618)
95a7407e0 is described below

commit 95a7407e0776ccd74a9357c9d7d57606d6053508
Author: GuojunLi <li...@bytedance.com>
AuthorDate: Tue Jul 25 16:01:00 2023 +0800

    [core] Add test for histogram metric (#1618)
    
    This closes #1618.
---
 .../DescriptiveStatisticsHistogramTest.java        | 119 +++++++++++++++++++++
 1 file changed, 119 insertions(+)

diff --git a/paimon-core/src/test/java/org/apache/paimon/metrics/DescriptiveStatisticsHistogramTest.java b/paimon-core/src/test/java/org/apache/paimon/metrics/DescriptiveStatisticsHistogramTest.java
new file mode 100644
index 000000000..341e9f988
--- /dev/null
+++ b/paimon-core/src/test/java/org/apache/paimon/metrics/DescriptiveStatisticsHistogramTest.java
@@ -0,0 +1,119 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF 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.apache.paimon.metrics;
+
+import org.apache.paimon.utils.InstantiationUtil;
+
+import org.assertj.core.data.Offset;
+import org.junit.jupiter.api.Test;
+import org.testcontainers.utility.ThrowingFunction;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.offset;
+
+/**
+ * Tests for {@link DescriptiveStatisticsHistogram} and {@link
+ * DescriptiveStatisticsHistogramStatistics}.
+ */
+class DescriptiveStatisticsHistogramTest {
+
+    private static final double[] DATA = {1, 2, 3, 4, 5, 6, 7, 8, 9};
+
+    @Test
+    void testDescriptiveHistogram() {
+        int size = 10;
+        testHistogram(size, new DescriptiveStatisticsHistogram(size));
+    }
+
+    @Test
+    void testSerialization() throws Exception {
+        testDuplication(
+                original -> {
+                    final byte[] bytes = InstantiationUtil.serializeObject(original);
+                    return InstantiationUtil.deserializeObject(bytes, getClass().getClassLoader());
+                });
+    }
+
+    @Test
+    void testCopy() throws Exception {
+        testDuplication(DescriptiveStatisticsHistogramStatistics.CommonMetricsSnapshot::copy);
+    }
+
+    private void testHistogram(int size, Histogram histogram) {
+        HistogramStatistics statistics;
+
+        for (int i = 0; i < size; i++) {
+            histogram.update(i);
+
+            statistics = histogram.getStatistics();
+            assertThat(histogram.getCount()).isEqualTo(i + 1);
+            assertThat(statistics.size()).isEqualTo(histogram.getCount());
+            assertThat(statistics.getMax()).isEqualTo(i);
+            assertThat(statistics.getMin()).isEqualTo(0);
+        }
+
+        statistics = histogram.getStatistics();
+        assertThat(statistics.size()).isEqualTo(size);
+        assertThat(statistics.getQuantile(0.5)).isCloseTo((size - 1) / 2.0, offset(0.001));
+
+        for (int i = size; i < 2 * size; i++) {
+            histogram.update(i);
+
+            statistics = histogram.getStatistics();
+            assertThat(histogram.getCount()).isEqualTo(i + 1);
+            assertThat(statistics.size()).isEqualTo(size);
+            assertThat(statistics.getMax()).isEqualTo(i);
+            assertThat(statistics.getMin()).isEqualTo(i + 1 - size);
+        }
+
+        statistics = histogram.getStatistics();
+        assertThat(statistics.size()).isEqualTo(size);
+        assertThat(statistics.getQuantile(0.5)).isCloseTo(size + (size - 1) / 2.0, offset(0.001));
+    }
+
+    private static void testDuplication(
+            ThrowingFunction<
+                            DescriptiveStatisticsHistogramStatistics.CommonMetricsSnapshot,
+                            DescriptiveStatisticsHistogramStatistics.CommonMetricsSnapshot>
+                    duplicator)
+            throws Exception {
+
+        DescriptiveStatisticsHistogramStatistics.CommonMetricsSnapshot original =
+                new DescriptiveStatisticsHistogramStatistics.CommonMetricsSnapshot();
+        original.evaluate(DATA);
+
+        assertOperations(original);
+
+        final DescriptiveStatisticsHistogramStatistics.CommonMetricsSnapshot copy =
+                duplicator.apply(original);
+
+        assertOperations(copy);
+    }
+
+    private static void assertOperations(
+            DescriptiveStatisticsHistogramStatistics.CommonMetricsSnapshot statistics) {
+        assertThat(statistics.getPercentile(0.5)).isEqualTo(1);
+        assertThat(statistics.getCount()).isEqualTo(9);
+        assertThat(statistics.getMin()).isEqualTo(1);
+        assertThat(statistics.getMax()).isEqualTo(9);
+        assertThat(statistics.getMean()).isEqualTo(5);
+        assertThat(statistics.getStandardDeviation()).isCloseTo(2.7, Offset.offset(0.5));
+        assertThat(statistics.getValues()).containsExactly(DATA);
+    }
+}