1 files changed, 50 insertions, 0 deletions
diff --git a/core/src/test/scala/org/apache/spark/util/collection/unsafe/sort/PrefixComparatorsSuite.scala b/core/src/test/scala/org/apache/spark/util/collection/unsafe/sort/PrefixComparatorsSuite.scala
new file mode 100644
index 0000000000..dd505dfa7d
--- /dev/null
+++ b/core/src/test/scala/org/apache/spark/util/collection/unsafe/sort/PrefixComparatorsSuite.scala
@@ -0,0 +1,50 @@
+/*
+ * 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.unsafe.sort
+
+import org.scalatest.prop.PropertyChecks
+
+import org.apache.spark.SparkFunSuite
+
+class PrefixComparatorsSuite extends SparkFunSuite with PropertyChecks {
+
+  test("String prefix comparator") {
+
+    def testPrefixComparison(s1: String, s2: String): Unit = {
+      val s1Prefix = PrefixComparators.STRING.computePrefix(s1)
+      val s2Prefix = PrefixComparators.STRING.computePrefix(s2)
+      val prefixComparisonResult = PrefixComparators.STRING.compare(s1Prefix, s2Prefix)
+      assert(
+        (prefixComparisonResult == 0) ||
+        (prefixComparisonResult < 0 && s1 < s2) ||
+        (prefixComparisonResult > 0 && s1 > s2))
+    }
+
+    // scalastyle:off
+    val regressionTests = Table(
+      ("s1", "s2"),
+      ("abc", "世界"),
+      ("你好", "世界"),
+      ("你好123", "你好122")
+    )
+    // scalastyle:on
+
+    forAll (regressionTests) { (s1: String, s2: String) => testPrefixComparison(s1, s2) }
+    forAll { (s1: String, s2: String) => testPrefixComparison(s1, s2) }
+  }
+}