UTF8String Property Checks.

unsafe/pom.xml

@@ -70,6 +70,10 @@
       <artifactId>mockito-core</artifactId>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <groupId>org.scalacheck</groupId>
+      <artifactId>scalacheck_${scala.binary.version}</artifactId>
+    </dependency>
   </dependencies>
   <build>
     <outputDirectory>target/scala-${scala.binary.version}/classes</outputDirectory>

unsafe/src/test/scala/org/apache/spark/unsafe/types/UTF8StringProperyChecks.scala

@@ -0,0 +1,66 @@
+package org.apache.spark.unsafe.types
+
+import org.scalatest.prop.GeneratorDrivenPropertyChecks
+import org.scalatest.{FunSuite, Matchers}
+import org.apache.spark.unsafe.types.UTF8String.{fromString => toUTF8}
+
+
+class UTF8StringSuite2 extends FunSuite with GeneratorDrivenPropertyChecks with Matchers {
+
+  test("toString") {
+    forAll { (s: String) =>
+      assert(s === toUTF8(s).toString())
+    }
+  }
+
+  test("numChars") {
+    forAll { (s: String) =>
+      assert(toUTF8(s).numChars() === s.length)
+    }
+  }
+
+  test("startsWith") {
+    forAll { (s: String) =>
+      val utf8 = toUTF8(s)
+      assert(utf8.startsWith(utf8))
+      for (i <- 1 to s.length) {
+        assert(utf8.startsWith(toUTF8(s.dropRight(i))))
+      }
+    }
+  }
+
+  test("endsWith") {
+    forAll { (s: String) =>
+      val utf8 = toUTF8(s)
+      assert(utf8.endsWith(utf8))
+      for (i <- 1 to s.length) {
+        assert(utf8.endsWith(toUTF8(s.drop(i))))
+      }
+    }
+  }
+
+  test("toUpperCase") {
+    forAll { (s: String) =>
+      assert(s.toUpperCase === toUTF8(s).toUpperCase.toString)
+    }
+  }
+
+  test("toLowerCase") {
+    forAll { (s: String) =>
+      assert(s.toLowerCase === toUTF8(s).toLowerCase.toString)
+    }
+  }
+
+  test("compare") {
+    forAll { (s1: String, s2: String) =>
+      assert(Math.signum(s1.compareTo(s2)) === Math.signum(toUTF8(s1).compareTo(toUTF8(s2))))
+    }
+  }
+
+  test("substring") {
+    forAll { (s: String) =>
+      assert(s.substring(0, 0) === toUTF8(s).substring(0, 0).toString)
+      assert(s.substring(0, s.length) === toUTF8(s).substring(0, s.length).toString)
+    }
+  }
+}