add random string test

core-kotlin/src/test/kotlin/com/baeldung/random/RandomStringTest.kt

@@ -0,0 +1,18 @@
+
+import org.junit.jupiter.api.Test
+import java.util.concurrent.ThreadLocalRandom
+import kotlin.test.assertTrue
+
+class RandomNumberTest {
+
+    @Test
+    fun whenRandomNumberWithJavaUtilMath_thenResultIsBetween0And1() {
+        val source = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+        var test = Random().ints(outputStrLength, 0, source.length)
+                .asSequence()
+                .map(source::get)
+                .joinToString("")
+        print("message")
+    }
+
+}