Add a runtime test for Objective-C class namespacing.

Swift SVN r15589

test/Interpreter/SDK/objc_mangling.swift

@@ -0,0 +1,26 @@
+// RUN: rm -rf %t  &&  mkdir %t
+// RUN: %target-build-swift -module-name MangleTest -enable-objc-mangling %s -o %t/a.out
+// RUN: %target-run %t/a.out | FileCheck %s
+import Foundation
+
+/* FIXME: SwiftObject doesn't support -description
+class Foo { }
+var anyFoo: AnyObject = Foo()
+println(anyFoo.description())
+
+@objc class Bar { }
+var anyBar: AnyObject = Bar()
+println(anyBar.description())
+*/
+
+// Check whether the class name comes out properly in the description
+// CHECK: _TtC10MangleTest6Wibble
+@objc class Wibble : NSObject { }
+var anyWibble: AnyObject = Wibble()
+println(anyWibble.description())
+
+// Check whether we can lookup the class with this name.
+var anyWibbleClass: AnyClass = NSClassFromString("_TtC10MangleTest6Wibble")
+var anyWibbleClass2 = anyWibble.`class`()
+assert(NSStringFromClass(anyWibbleClass) == "_TtC10MangleTest6Wibble")
+assert(NSStringFromClass(anyWibbleClass2) == "_TtC10MangleTest6Wibble")