Merge pull request #493 from trentxintong/master

Renable tests after investigation. rdar://27604350

Author: trentxintong

TestFoundation/TestNSJSONSerialization.swift

@@ -291,39 +291,35 @@ extension TestNSJSONSerialization {
     }
 
     func test_deserialize_unicodeEscapeSequence() {
-        // DISABLED: changes for SE-128 have apparently changed the result of parsing
-        // TODO: Investigate and re-enable test.
-        /*
         let subject = "[\"\\u2728\"]"
         do {
             guard let data = subject.data(using: .utf8) else {
                 XCTFail("Unable to convert string to data")
                 return
             }
             let result = try JSONSerialization.jsonObject(with: data, options: []) as? [Any]
+            // result?[0] as? String returns an Optional<String> and RHS is promoted
+            // to Optional<String>
             XCTAssertEqual(result?[0] as? String, "✨")
         } catch {
             XCTFail("Unexpected error: \(error)")
         }
-        */
     }
 
     func test_deserialize_unicodeSurrogatePairEscapeSequence() {
-        // DISABLED: changes for SE-128 have apparently changed the result of parsing
-        // TODO: Investigate and re-enable test.
-        /*
         let subject = "[\"\\uD834\\udd1E\"]"
         do {
             guard let data = subject.data(using: .utf8) else {
                 XCTFail("Unable to convert string to data")
                 return
             }
             let result = try JSONSerialization.jsonObject(with: data, options: []) as? [Any]
+            // result?[0] as? String returns an Optional<String> and RHS is promoted
+            // to Optional<String>
             XCTAssertEqual(result?[0] as? String, "\u{1D11E}")
         } catch {
             XCTFail("Unexpected error: \(error)")
         }
-        */
     }
 
     func test_deserialize_allowFragments() {