Add (failing) test for keysSortedByValueUsingComparator:

Tests/base/NSDictionary/sort.m

@@ -0,0 +1,41 @@
+#import "Testing.h"
+#import "ObjectTesting.h"
+#import <Foundation/NSAutoreleasePool.h>
+#import <Foundation/NSDictionary.h>
+
+int main()
+{
+  NSAutoreleasePool   *arp = [NSAutoreleasePool new];
+
+  NSArray* values = [NSArray arrayWithObjects:
+        [NSNumber numberWithFloat:2.0],
+        [NSNumber numberWithFloat:1.0],
+        [NSNumber numberWithFloat:3.0],
+        [NSNumber numberWithFloat:4.0],
+        nil];
+
+  NSArray* keys = [NSArray arrayWithObjects:
+        @"shouldSortToSecond",
+        @"shouldSortToFirst",
+        @"shouldSortToThird",
+        @"shouldSortToFourth",
+        nil];
+
+  NSDictionary *d = [NSDictionary dictionaryWithObjects:values forKeys:keys];
+  NSArray* keysOrderedByKeyedValue = [d keysSortedByValueUsingComparator:
+                      ^NSComparisonResult(id obj1, id obj2) {
+                              return [(NSNumber*)obj1 compare:(NSNumber*)obj2];
+                      }];
+
+  NSArray* expected = [NSArray arrayWithObjects:
+        @"shouldSortToFirst",
+        @"shouldSortToSecond",
+        @"shouldSortToThird",
+        @"shouldSortToFourth",
+        nil];
+
+  PASS([keysOrderedByKeyedValue isEqual:expected], "Can sort a dictionary's keys by its values");
+
+  [arp release]; arp = nil;
+  return 0;
+}