String <-> CharArray conversion, ArrayBuilder by @elizarov (#98)

backend.native/tests/runtime/text/string_builder0.kt

@@ -0,0 +1,46 @@
+fun assertTrue(cond: Boolean) {
+    if (!cond)
+        println("FAIL")
+}
+
+fun assertFalse(cond: Boolean) {
+    if (cond)
+        println("FAIL")
+}
+
+fun assertEquals(value1: String, value2: String) {
+    if (value1 != value2)
+        println("FAIL: '" + value1 + "' != '" + value2 + "'")
+}
+
+fun assertEquals(value1: Int, value2: Int) {
+    if (value1 != value2)
+        println("FAIL" + value1.toString() + " != " + value2.toString())
+}
+
+fun testBasic() {
+    val sb = StringBuilder()
+    assertEquals(0, sb.length)
+    assertEquals("", sb.toString())
+    sb.append(1)
+    assertEquals(1, sb.length)
+    assertEquals("1", sb.toString())
+    sb.append(", ")
+    assertEquals(3, sb.length)
+    assertEquals("1, ", sb.toString())
+    sb.append(true)
+    assertEquals(7, sb.length)
+    assertEquals("1, true", sb.toString())
+    sb.append(12345678L)
+    assertEquals(15, sb.length)
+    assertEquals("1, true12345678", sb.toString())
+
+    sb.length = 0
+    assertEquals(0, sb.length)
+    assertEquals("", sb.toString())
+}
+
+fun main(args : Array<String>) {
+    testBasic()
+    println("OK")
+}