Implement NSArray's customMirror

Author: noppefoxwolf

Foundation/NSArray.swift

@@ -950,7 +950,9 @@ extension NSArray : ExpressibleByArrayLiteral {
 }
 
 extension NSArray : CustomReflectable {
-    public var customMirror: Mirror { NSUnimplemented() }
+    public var customMirror: Mirror {
+        return Mirror(reflecting: Array(self))
+    }
 }
 
 extension NSArray : _StructTypeBridgeable {

TestFoundation/TestNSArray.swift

@@ -42,6 +42,7 @@ class TestNSArray : XCTestCase {
             ("test_insertObjectsAtIndexes", test_insertObjectsAtIndexes),
             ("test_replaceObjectsAtIndexesWithObjects", test_replaceObjectsAtIndexesWithObjects),
             ("test_pathsMatchingExtensions", test_pathsMatchingExtensions),
+            ("test_customMirror", test_customMirror),
         ]
     }
 
@@ -793,6 +794,22 @@ class TestNSArray : XCTestCase {
         let match5 = paths.pathsMatchingExtensions(["..txt"])
         XCTAssertEqual(match5, [])
     }
+    
+    func test_customMirror() {
+        let inputArray = ["this", "is", "a", "test", "of", "copy", "with", "strings"]
+        let array = NSArray(array: inputArray)
+        let arrayMirror = array.customMirror
+        dump(arrayMirror.children)
+        
+        XCTAssertEqual(array[0] as! String, arrayMirror.descendant(0) as! String)
+        XCTAssertEqual(array[1] as! String, arrayMirror.descendant(1) as! String)
+        XCTAssertEqual(array[2] as! String, arrayMirror.descendant(2) as! String)
+        XCTAssertEqual(array[3] as! String, arrayMirror.descendant(3) as! String)
+        XCTAssertEqual(array[4] as! String, arrayMirror.descendant(4) as! String)
+        XCTAssertEqual(array[5] as! String, arrayMirror.descendant(5) as! String)
+        XCTAssertEqual(array[6] as! String, arrayMirror.descendant(6) as! String)
+        XCTAssertEqual(array[7] as! String, arrayMirror.descendant(7) as! String)
+    }
 
     private func createTestFile(_ path: String, _contents: Data) -> String? {
         let tempDir = NSTemporaryDirectory() + "TestFoundation_Playground_" + NSUUID().uuidString + "/"