Add NSUserDefaults KVO tests

Tests/base/NSKVOSupport/userdefaults.m

@@ -0,0 +1,177 @@
+#import <Foundation/NSObject.h>
+#import <Foundation/NSString.h>
+#import <Foundation/NSValue.h>
+#import <Foundation/NSDictionary.h>
+#import <Foundation/NSUserDefaults.h>
+#import <Foundation/NSKeyValueObserving.h>
+
+#import <Testing.h>
+
+/* NSUserDefaults KeyValueObserving Tests
+ *
+ * Behaviour was validated on macOS 15.0.1 (24A348)
+ */
+
+@interface Observer : NSObject
+{
+@public
+  NSInteger     called;
+  NSString     *lastKeyPath;
+  id            lastObject;
+  NSDictionary *lastChange;
+}
+@end
+
+@implementation Observer
+
+- (void)observeValueForKeyPath:(NSString *)keyPath
+                      ofObject:(id)object
+                        change:(NSDictionary *)change
+                       context:(void *)context
+{
+  NSLog(@"KVO notification: keyPath: %@ ofObject: %@ change: %@ context: %p",
+        keyPath, object, change, context);
+  called++;
+  ASSIGN(lastKeyPath, keyPath);
+  ASSIGN(lastObject, object);
+  ASSIGN(lastChange, change);
+}
+
+- (void)dealloc
+{
+  RELEASE(lastKeyPath);
+  RELEASE(lastObject);
+  RELEASE(lastChange);
+  [super dealloc];
+}
+
+@end
+
+// NSUserDefaults Domain Search List:
+// NSArgumentDomain
+// Application Domain
+// NSGlobalDomain
+// NSRegistrationDomain
+//
+// Terminology:
+// - Entry: An entry is a key value pair.
+// - Object and Value: both used interchangeably in the NSUserDefaults API to
+// describe the value associated with a given key.
+//
+// Note that -removeObjectForKey: and -setObject:ForKey: emit only a
+// KVO notification when the value has actually changed, meaning
+// -objectForKey: would return a different value than before.
+//
+// Example:
+// Assume that a key with the same value is registered in both NSArgumentDomain
+// and the application domain. If we remove the value with -removeObjectForKey:,
+// we set the value for the key in the application domain to nil, but we stil
+// have an entry in the NSArgumentDomain. Thus -objectForKey will return the
+// same value as before and no change notification is emitted.
+int
+main(int argc, char *argv[])
+{
+  NSUserDefaults *defs = [NSUserDefaults standardUserDefaults];
+  Observer       *obs = [Observer new];
+  NSString       *key1 = @"key1";
+  NSString       *value1 = @"value1";
+  NSString       *key2 = @"key2";
+  NSString       *value2 = @"value2";
+  NSString       *value2Alt = @"value2Alt";
+
+  [defs addObserver:obs
+         forKeyPath:key1
+            options:NSKeyValueObservingOptionNew | NSKeyValueObservingOptionOld
+            context:NULL];
+  [defs addObserver:obs
+         forKeyPath:key2
+            options:NSKeyValueObservingOptionNew | NSKeyValueObservingOptionOld
+            context:NULL];
+
+  // Check if we receive KVO notifications when setting default key in the
+  // standard application domain
+  [defs setObject:value1 forKey:key1];
+  PASS(obs->called == 1, "KVO notification received");
+  PASS(obs->lastObject != nil, "object is not nil");
+  PASS(obs->lastChange != nil, "change is not nil");
+  PASS_EQUAL([obs->lastChange objectForKey:@"kind"],
+             [NSNumber numberWithInteger:1], "value for 'kind' is 1");
+  PASS_EQUAL([obs->lastChange objectForKey:@"old"], nil,
+             "value for 'old' is nil");
+  PASS_EQUAL([obs->lastChange objectForKey:@"new"], value1,
+             "value for 'new' is 'value1'");
+
+  [defs removeObjectForKey:key1];
+  PASS(obs->called == 2, "KVO notification received");
+  PASS(obs->lastObject != nil, "object is not nil");
+  PASS(obs->lastChange != nil, "change is not nil");
+  PASS_EQUAL([obs->lastChange objectForKey:@"kind"],
+             [NSNumber numberWithInteger:1], "value for 'kind' is 1");
+  PASS_EQUAL([obs->lastChange objectForKey:@"old"], value1,
+             "value for 'old' is value1");
+  PASS_EQUAL([obs->lastChange objectForKey:@"new"], nil,
+             "value for 'new' is nil");
+
+  // Test setting two different values for the same key in application domain
+  // and registration domain. When removing the value in the application domain,
+  // the value for 'new' in the change dictionary is not nil, but rather the
+  // value from the registration domain.
+  [defs setObject:value2 forKey:key2];
+  PASS(obs->called == 3, "KVO notification received");
+  PASS(obs->lastObject != nil, "object is not nil");
+  PASS(obs->lastChange != nil, "change is not nil");
+  PASS_EQUAL([obs->lastChange objectForKey:@"kind"],
+             [NSNumber numberWithInteger:1], "value for 'kind' is 1");
+  PASS_EQUAL([obs->lastChange objectForKey:@"old"], nil,
+             "value for 'old' is nil");
+  PASS_EQUAL([obs->lastChange objectForKey:@"new"], value2,
+             "value for 'new' is 'value2'");
+
+  // Set default key in registration domain that is _different_ to the key
+  // registered in the application domain. This will trigger a change
+  // notification, when the entry is removed from the application domain.
+  NSDictionary *registrationDict = [NSDictionary dictionaryWithObject:value2Alt
+                                                               forKey:key2];
+  // -registerDefaults: does not emit a KVO notification
+  [defs registerDefaults:registrationDict];
+
+  [defs removeObjectForKey:key2];
+  PASS(obs->called == 4, "KVO notification received");
+  PASS(obs->lastObject != nil, "object is not nil");
+  PASS(obs->lastChange != nil, "change is not nil");
+  PASS_EQUAL([obs->lastChange objectForKey:@"kind"],
+             [NSNumber numberWithInteger:1], "value for 'kind' is 1");
+  PASS_EQUAL([obs->lastChange objectForKey:@"old"], value2,
+             "value for 'old' is nil");
+  // this must not be null in this case
+  PASS_EQUAL([obs->lastChange objectForKey:@"new"], value2Alt,
+             "value for 'new' is 'value2Alt'");
+
+  // Set default key in registration domain that is _equal_ to the key
+  // registered in the application domain. This will _not_ trigger a change
+  // notification, when the entry is removed from the application domain.
+  registrationDict = [NSDictionary dictionaryWithObject:value1 forKey:key1];
+  [defs registerDefaults:registrationDict];
+
+  [defs setObject:value1 forKey:key1];
+  PASS(obs->called == 5, "KVO notification received");
+  PASS(obs->lastObject != nil, "object is not nil");
+  PASS(obs->lastChange != nil, "change is not nil");
+  PASS_EQUAL([obs->lastChange objectForKey:@"kind"],
+             [NSNumber numberWithInteger:1], "value for 'kind' is 1");
+  PASS_EQUAL([obs->lastChange objectForKey:@"old"], nil,
+             "value for 'old' is nil");
+  PASS_EQUAL([obs->lastChange objectForKey:@"new"], value1,
+             "value for 'new' is 'value1'");
+
+  // Remove the entry from the application domain.
+  [defs removeObjectForKey:key1];
+  PASS(obs->called == 5,
+       "KVO notification was not emitted when other domain has the same entry");
+
+  [defs removeObserver:obs forKeyPath:key1];
+  [defs removeObserver:obs forKeyPath:key2];
+
+  [obs release];
+  return 0;
+}