Provide common Random API

#KT-17261

libraries/stdlib/samples/test/samples/random/randoms.kt

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2010-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
+ */
+
+package samples.random
+
+import samples.*
+import kotlin.random.Random
+import kotlin.test.assertTrue
+
+class Randoms {
+    @Sample
+    fun defaultRandom() {
+        val randomValues = List(10) { Random.nextInt(0, 100) }
+        // prints new sequence every time
+        println(randomValues)
+
+        val nextValues = List(10) { Random.nextInt(0, 100) }
+        println(nextValues)
+        assertTrue(randomValues != nextValues)
+    }
+
+    @Sample
+    fun seededRandom() {
+        fun getRandomList(random: Random): List<Int> =
+            List(10) { random.nextInt(0, 100) }
+
+        val randomValues1 = getRandomList(Random(42))
+        // prints the same sequence every time
+        assertPrints(randomValues1, "[44, 34, 69, 67, 22, 16, 67, 45, 95, 10]")
+
+        val randomValues2 = getRandomList(Random(42))
+        // random with the same seed produce the same sequence
+        assertTrue(randomValues1 == randomValues2)
+
+        val randomValues3 = getRandomList(Random(0))
+        // random with another seed produce another sequence
+        assertPrints(randomValues3, "[20, 63, 41, 28, 0, 99, 35, 42, 72, 13]")
+    }
+}