[stdlib] Added NSEnumerator to SequenceType

Fixes rdar://problem/17925006

Swift SVN r23497

test/1_stdlib/NSEnumeratorAPI.swift

@@ -0,0 +1,25 @@
+// RUN: %target-run-simple-swift
+
+import StdlibUnittest
+import Foundation
+
+var NSEnumeratorAPI = TestSuite("NSEnumeratorAPI")
+
+NSEnumeratorAPI.test("SequenceType") {
+  let result = NSDictionary().keyEnumerator()
+  isSequenceType(result)
+}
+
+NSEnumeratorAPI.test("keyEnumerator") {
+  let result = [1: "one", 2: "two"]
+  expectEqualsUnordered(
+    [1, 2], NSDictionary(dictionary: result).keyEnumerator()) {
+    switch ($0 as Int, $1 as Int) {
+    case let (x, y) where x == y: return .EQ
+    case let (x, y) where x < y: return .LT
+    case _: return .GT
+    }
+  }
+}
+
+runAllTests()