Adding testcase for extends helper emit when generating system module

Testcase for #3655

tests/baselines/reference/systemModuleWithSuperClass.js

@@ -0,0 +1,55 @@
+//// [tests/cases/compiler/systemModuleWithSuperClass.ts] ////
+
+//// [foo.ts]
+
+export class Foo {
+    a: string;
+}
+
+//// [bar.ts]
+import {Foo} from './foo';
+export class Bar extends Foo {
+    b: string;
+}
+
+//// [foo.js]
+System.register([], function(exports_1) {
+    var Foo;
+    return {
+        setters:[],
+        execute: function() {
+            Foo = (function () {
+                function Foo() {
+                }
+                return Foo;
+            })();
+            exports_1("Foo", Foo);
+        }
+    }
+});
+//// [bar.js]
+var __extends = (this && this.__extends) || function (d, b) {
+    for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
+    function __() { this.constructor = d; }
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
+};
+System.register(['./foo'], function(exports_1) {
+    var foo_1;
+    var Bar;
+    return {
+        setters:[
+            function (_foo_1) {
+                foo_1 = _foo_1;
+            }],
+        execute: function() {
+            Bar = (function (_super) {
+                __extends(Bar, _super);
+                function Bar() {
+                    _super.apply(this, arguments);
+                }
+                return Bar;
+            })(foo_1.Foo);
+            exports_1("Bar", Bar);
+        }
+    }
+});

tests/baselines/reference/systemModuleWithSuperClass.symbols

@@ -0,0 +1,20 @@
+=== tests/cases/compiler/foo.ts ===
+
+export class Foo {
+>Foo : Symbol(Foo, Decl(foo.ts, 0, 0))
+
+    a: string;
+>a : Symbol(a, Decl(foo.ts, 1, 18))
+}
+
+=== tests/cases/compiler/bar.ts ===
+import {Foo} from './foo';
+>Foo : Symbol(Foo, Decl(bar.ts, 0, 8))
+
+export class Bar extends Foo {
+>Bar : Symbol(Bar, Decl(bar.ts, 0, 26))
+>Foo : Symbol(Foo, Decl(bar.ts, 0, 8))
+
+    b: string;
+>b : Symbol(b, Decl(bar.ts, 1, 30))
+}

tests/baselines/reference/systemModuleWithSuperClass.types

@@ -0,0 +1,20 @@
+=== tests/cases/compiler/foo.ts ===
+
+export class Foo {
+>Foo : Foo
+
+    a: string;
+>a : string
+}
+
+=== tests/cases/compiler/bar.ts ===
+import {Foo} from './foo';
+>Foo : typeof Foo
+
+export class Bar extends Foo {
+>Bar : Bar
+>Foo : Foo
+
+    b: string;
+>b : string
+}

tests/cases/compiler/systemModuleWithSuperClass.ts

@@ -0,0 +1,12 @@
+// @module: system
+
+// @Filename: foo.ts
+export class Foo {
+    a: string;
+}
+
+// @Filename: bar.ts
+import {Foo} from './foo';
+export class Bar extends Foo {
+    b: string;
+}