Merge pull request #1711 from ddunn2/valueForKey

Author: swift-ci

Foundation/NSDictionary.swift

@@ -33,7 +33,12 @@ open class NSDictionary : NSObject, NSCopying, NSMutableCopying, NSSecureCoding,
     }
 
     open func value(forKey key: String) -> Any? {
-        NSUnsupported()
+        if key.hasPrefix("@") {
+            NSUnsupported()
+        } else {
+            return object(forKey: key)
+        }
+        
     }
 
     open func keyEnumerator() -> NSEnumerator {

TestFoundation/TestNSDictionary.swift

@@ -21,6 +21,8 @@ class TestNSDictionary : XCTestCase {
             ("test_writeToFile", test_writeToFile),
             ("test_initWithContentsOfFile", test_initWithContentsOfFile),
             ("test_settingWithStringKey", test_settingWithStringKey),
+            ("test_valueForKey", test_valueForKey),
+            ("test_valueForKeyWithNestedDict", test_valueForKeyWithNestedDict),
         ]
     }
 
@@ -217,6 +219,19 @@ class TestNSDictionary : XCTestCase {
         // has crashed in the past
         dict["stringKey"] = "value"
     }
+    
+    func test_valueForKey() {
+        let dict: NSDictionary = ["foo": "bar"]
+        let result = dict.value(forKey: "foo")
+        XCTAssertEqual(result as? String, "bar")
+    }
+    
+    func test_valueForKeyWithNestedDict() {
+        let dict: NSDictionary = ["foo": ["bar": "baz"]]
+        let result = dict.value(forKey: "foo")
+        let expectedResult: NSDictionary = ["bar": "baz"]
+        XCTAssertEqual(result as? NSDictionary, expectedResult)
+    }
 
     private func createTestFile(_ path: String, _contents: Data) -> String? {
         let tempDir = NSTemporaryDirectory() + "TestFoundation_Playground_" + NSUUID().uuidString + "/"