Fix wrong change is sent to observer when top level object is changed.

When you change the top level object, observer MUST receive value
for the key path of the previous top level object as old and
value for the key path of the new top level object as new.

Foundation/CPKeyValueObserving.j

@@ -1114,7 +1114,14 @@ var kvoNewAndOld        = CPKeyValueObservingOptionNew | CPKeyValueObservingOpti
 {
     if (aKeyPath === _firstPart)
     {
-        [_observer observeValueForKeyPath:_firstPart ofObject:_object change:changes context:_context];
+        var oldValue = [_value valueForKeyPath:_secondPart],
+            newValue = [_object valueForKeyPath:_firstPart+"."+_secondPart],
+            pathChanges = [CPDictionary dictionaryWithObjectsAndKeys:
+                            newValue ? newValue : [CPNull null],    CPKeyValueChangeNewKey,
+                            oldValue ? oldValue : [CPNull null],    CPKeyValueChangeOldKey,
+                            CPKeyValueChangeSetting,                CPKeyValueChangeKindKey];
+
+        [_observer observeValueForKeyPath:_firstPart+"."+_secondPart ofObject:_object change:pathChanges context:_context];
 
         //since a has changed, we should remove ourselves as an observer of the old a, and observe the new one
         if (_value)

Tests/Foundation/CPKVOTest.j

@@ -290,7 +290,10 @@
 
     [a addObserver:self forKeyPath:"b.c.d.e.f" options:0 context:"testCrazyKeyPathChanges"];
 
-    [a setValue:[D new] forKeyPath:"b.c.d"];
+    var newD = [D new];
+    [newD setValue:[E new] forKeyPath:@"e"];
+    [newD setValue:[F new] forKeyPath:@"e.f"];
+    [a setValue:newD forKeyPath:"b.c.d"];
 
     [self assertTrue: _sawObservation message:"Never recieved an observation"];
 }
@@ -382,6 +385,22 @@
     [self assertTrue: _sawObservation message:"Never recieved an observation"];
 }
 
+- (void)testChangeTopLevelObject
+{
+    var tester = [IndirectToManyTester new];
+
+    tester.tester = [ToManyTester new];
+
+    [tester.tester setValue:[1, 2, 3, 4] forKey:@"subviews"];
+    [tester addObserver:self forKeyPath:@"tester.subviews" options:0 context:"testChangeTopLevelObject"];
+
+    var newTesterTester = [ToManyTester new];
+    [newTesterTester setValue:[5, 6, 7, 8] forKey:@"subviews"];
+    [tester setValue:newTesterTester forKey:@"tester"];
+
+    [self assertTrue: _sawObservation message:"Never recieved an observation"];
+}
+
 - (void)testPerformance
 {
     bob = [PersonTester new];
@@ -537,21 +556,21 @@
             break;
 
         case "testThreePartKeyPart2":
-            [self assertTrue: aKeyPath == "teacher.car" message:"Keypath should be: teacher.car, was: "+aKeyPath];
-            [self assertTrue: newValue.year == "2000" message:"New value should be a car with year: 2000, was: "+[newValue description]];
+            [self assertTrue: aKeyPath == "teacher.car.year" message:"Keypath should be: teacher.car, was: "+aKeyPath];
+            [self assertTrue: newValue == "2000" message:"New value should be a car with year: 2000, was: "+[newValue description]];
             [self assertTrue: anObject == cs101 message: "anObject should be: "+[cs101 description]+", was: "+[anObject description]];
             break;
 
         case "testCrazyKeyPathChanges":
             [self assertTrue: [anObject class] == A message:"Should be observing an A class, was: "+[anObject class]];
-            [self assertTrue: [newValue class] == D message:"Changed class was a D class, got: "+[newValue class]];
-            [self assertTrue: aKeyPath == "b.c.d" message:"Expected keyPath b.c.d, got: "+aKeyPath];
+            [self assertTrue: [newValue class] == F message:"Changed class was a F class, got: "+[newValue class]];
+            [self assertTrue: aKeyPath == "b.c.d.e.f" message:"Expected keyPath b.c.d.e.f, got: "+aKeyPath];
             break;
 
         case "testCrazyKeyPathChanges2":
             [self assertTrue: [anObject class] == A message:"Should be observing an A class, was: "+[anObject class]];
             [self assertTrue: newValue == [CPNull null] message:"Expected null, got: "+newValue];
-            [self assertTrue: aKeyPath == "b.c" message:"Expected keyPath b.c, got: "+aKeyPath];
+            [self assertTrue: aKeyPath == "b.c.d.e.f" message:"Expected keyPath b.c.d.e.f, got: "+aKeyPath];
             break;
 
         case "testCrazyKeyPathChanges3":
@@ -616,6 +635,17 @@
 
             break;
 
+        case "testChangeTopLevelObject":
+            var type = [changes objectForKey:CPKeyValueChangeKindKey];
+            [self assertTrue: type == CPKeyValueChangeSetting message: "Should have been a set, was: "+type];
+
+            var oldValue = [changes objectForKey:CPKeyValueChangeOldKey],
+                newValue = [changes objectForKey:CPKeyValueChangeNewKey];
+            [self assert:oldValue equals:[1, 2, 3, 4]];
+            [self assert:newValue equals:[5, 6, 7, 8]];
+
+            break;
+
         case "testRemoveFromToManyProperty":
             var type = [changes objectForKey:CPKeyValueChangeKindKey];
             [self assertTrue: type == CPKeyValueChangeRemoval message: "Should have been a removal, was: "+type];