Github user squito commented on a diff in the pull request:
https://github.com/apache/spark/pull/16867#discussion_r106436689
--- Diff:
core/src/test/scala/org/apache/spark/util/collection/MedianHeapSuite.scala ---
@@ -0,0 +1,67 @@
+/*
+ * 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.spark.util.collection
+
+import java.util.Arrays
+import java.util.NoSuchElementException
+
+import scala.collection.mutable.ArrayBuffer
+import scala.util.Random
+
+import org.apache.spark.SparkFunSuite
+
+class MedianHeapSuite extends SparkFunSuite {
+
+ test("If no numbers in MedianHeap, NoSuchElementException is thrown.") {
+ val medianHeap = new MedianHeap()
+ var valid = false
+ try {
+ medianHeap.median
+ } catch {
+ case e: NoSuchElementException =>
+ valid = true
+ }
+
+ assert(valid)
+ }
+
+ test("Median should be correct when size of MedianHeap is even") {
+ val array = Array(0, 1, 2, 3, 4, 5, 6, 7, 8, 9)
+ val medianHeap = new MedianHeap()
+ array.foreach(medianHeap.insert(_))
+ assert(medianHeap.size() === 10)
+ assert(medianHeap.median === ((array(4) + array(5)) / 2.0))
+ }
+
+ test("Median should be correct when size of MedianHeap is odd") {
+ val array = Array(0, 1, 2, 3, 4, 5, 6, 7, 8)
+ val medianHeap = new MedianHeap()
+ array.foreach(medianHeap.insert(_))
+ assert(medianHeap.size() === 9)
+ assert(medianHeap.median === (array(4)))
+ }
+
+ test("Size of Median should be correct though there are duplicated
numbers inside.") {
+ val array = Array(0, 0, 1, 1, 2, 2, 3, 3, 4, 4)
+ val medianHeap = new MedianHeap()
+ array.foreach(medianHeap.insert(_))
+ Arrays.sort(array)
+ assert(medianHeap.size === 10)
+ assert(medianHeap.median === ((array(4) + array(5)) / 2.0))
+ }
--- End diff --
I know Kay asked for tests with a some hardcoded data, but I think these
tests are too simplistic. All of these tests insert data in order, and none
have significant skew.
Can you add a test case which does something like:
1) inserts 10 elements with the same value (eg. 5), check the median
2) insert 100 elements with a larger value (eg 10) check the median
3) insert 1000 elements with an even smaller value (eg 0), check the median
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