[JS BE] add tests for es6-classes

js/js.translator/testData/box/es6classes/delegation.kt

@@ -0,0 +1,32 @@
+// EXPECTED_REACHABLE_NODES: 1359
+open class A(val x: Int) {
+    constructor(): this(100)
+}
+
+class PrimaryToPrimary(val p: Int): A(p * p)
+class PrimaryToSecondary(val p: Int): A()
+
+class SecondaryToPrimary : A {
+    constructor() : super(8)
+}
+class SecondaryToSecondary: A {
+    constructor() : super()
+}
+
+fun box(): String {
+    val ptp = PrimaryToPrimary(5)
+    assertEquals(ptp.p, 5)
+    assertEquals(ptp.x, 25)
+
+    val pts = PrimaryToSecondary(9)
+    assertEquals(pts.p, 9)
+    assertEquals(pts.x, 100)
+
+    val stp = SecondaryToPrimary()
+    assertEquals(stp.x, 8)
+
+    val sts = SecondaryToSecondary()
+    assertEquals(sts.x, 100)
+
+    return "OK"
+}