1 files changed, 128 insertions, 0 deletions
diff --git a/sql/catalyst/src/test/java/org/apache/spark/sql/catalyst/expressions/HiveHasherSuite.java b/sql/catalyst/src/test/java/org/apache/spark/sql/catalyst/expressions/HiveHasherSuite.java
new file mode 100644
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--- /dev/null
+++ b/sql/catalyst/src/test/java/org/apache/spark/sql/catalyst/expressions/HiveHasherSuite.java
@@ -0,0 +1,128 @@
+/*
+ * 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.sql.catalyst.expressions;
+
+import org.apache.spark.unsafe.Platform;
+import org.apache.spark.unsafe.types.UTF8String;
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.nio.charset.StandardCharsets;
+import java.util.HashSet;
+import java.util.Random;
+import java.util.Set;
+
+public class HiveHasherSuite {
+  private final static HiveHasher hasher = new HiveHasher();
+
+  @Test
+  public void testKnownIntegerInputs() {
+    int[] inputs = {0, Integer.MIN_VALUE, Integer.MAX_VALUE, 593689054, -189366624};
+    for (int input : inputs) {
+      Assert.assertEquals(input, HiveHasher.hashInt(input));
+    }
+  }
+
+  @Test
+  public void testKnownLongInputs() {
+    Assert.assertEquals(0, HiveHasher.hashLong(0L));
+    Assert.assertEquals(41, HiveHasher.hashLong(-42L));
+    Assert.assertEquals(42, HiveHasher.hashLong(42L));
+    Assert.assertEquals(-2147483648, HiveHasher.hashLong(Long.MIN_VALUE));
+    Assert.assertEquals(-2147483648, HiveHasher.hashLong(Long.MAX_VALUE));
+  }
+
+  @Test
+  public void testKnownStringAndIntInputs() {
+    int[] inputs = {84, 19, 8};
+    int[] expected = {-823832826, -823835053, 111972242};
+
+    for (int i = 0; i < inputs.length; i++) {
+      UTF8String s = UTF8String.fromString("val_" + inputs[i]);
+      int hash = HiveHasher.hashUnsafeBytes(s.getBaseObject(), s.getBaseOffset(), s.numBytes());
+      Assert.assertEquals(expected[i], ((31 * inputs[i]) + hash));
+    }
+  }
+
+  @Test
+  public void randomizedStressTest() {
+    int size = 65536;
+    Random rand = new Random();
+
+    // A set used to track collision rate.
+    Set<Integer> hashcodes = new HashSet<>();
+    for (int i = 0; i < size; i++) {
+      int vint = rand.nextInt();
+      long lint = rand.nextLong();
+      Assert.assertEquals(HiveHasher.hashInt(vint), HiveHasher.hashInt(vint));
+      Assert.assertEquals(HiveHasher.hashLong(lint), HiveHasher.hashLong(lint));
+
+      hashcodes.add(HiveHasher.hashLong(lint));
+    }
+
+    // A very loose bound.
+    Assert.assertTrue(hashcodes.size() > size * 0.95);
+  }
+
+  @Test
+  public void randomizedStressTestBytes() {
+    int size = 65536;
+    Random rand = new Random();
+
+    // A set used to track collision rate.
+    Set<Integer> hashcodes = new HashSet<>();
+    for (int i = 0; i < size; i++) {
+      int byteArrSize = rand.nextInt(100) * 8;
+      byte[] bytes = new byte[byteArrSize];
+      rand.nextBytes(bytes);
+
+      Assert.assertEquals(
+          HiveHasher.hashUnsafeBytes(bytes, Platform.BYTE_ARRAY_OFFSET, byteArrSize),
+          HiveHasher.hashUnsafeBytes(bytes, Platform.BYTE_ARRAY_OFFSET, byteArrSize));
+
+      hashcodes.add(HiveHasher.hashUnsafeBytes(
+          bytes, Platform.BYTE_ARRAY_OFFSET, byteArrSize));
+    }
+
+    // A very loose bound.
+    Assert.assertTrue(hashcodes.size() > size * 0.95);
+  }
+
+  @Test
+  public void randomizedStressTestPaddedStrings() {
+    int size = 64000;
+    // A set used to track collision rate.
+    Set<Integer> hashcodes = new HashSet<>();
+    for (int i = 0; i < size; i++) {
+      int byteArrSize = 8;
+      byte[] strBytes = String.valueOf(i).getBytes(StandardCharsets.UTF_8);
+      byte[] paddedBytes = new byte[byteArrSize];
+      System.arraycopy(strBytes, 0, paddedBytes, 0, strBytes.length);
+
+      Assert.assertEquals(
+          HiveHasher.hashUnsafeBytes(paddedBytes, Platform.BYTE_ARRAY_OFFSET, byteArrSize),
+          HiveHasher.hashUnsafeBytes(paddedBytes, Platform.BYTE_ARRAY_OFFSET, byteArrSize));
+
+      hashcodes.add(HiveHasher.hashUnsafeBytes(
+          paddedBytes, Platform.BYTE_ARRAY_OFFSET, byteArrSize));
+    }
+
+    // A very loose bound.
+    Assert.assertTrue(hashcodes.size() > size * 0.95);
+  }
+}