Added test case for NSMutableSet mapping on managed object. refs #1201

Tests/Logic/CoreData/RKEntityMappingTest.m

@@ -587,4 +587,22 @@
     expect(caughtException.reason).to.equal(@"`requestMapping` is not meant to be invoked on `RKEntityMapping`. You probably want to invoke `[RKObjectMapping requestMapping]`.");
 }
 
+- (void)testMappingArrayToMutableArray
+{
+    RKManagedObjectStore *managedObjectStore = [RKTestFactory managedObjectStore];
+    RKObjectMapping *mapping = [RKEntityMapping mappingForEntityForName:@"Human" inManagedObjectStore:managedObjectStore];
+    [mapping addAttributeMappingsFromDictionary:@{ @"favoriteColors": @"mutableFavoriteColors" }];
+    
+    NSDictionary *dictionary = @{ @"favoriteColors": @[ @"Blue", @"Red" ] };
+    RKHuman *human = [NSEntityDescription insertNewObjectForEntityForName:@"Human" inManagedObjectContext:managedObjectStore.mainQueueManagedObjectContext];
+    RKMappingOperation *operation = [[RKMappingOperation alloc] initWithSourceObject:dictionary destinationObject:human mapping:mapping];
+    RKManagedObjectMappingOperationDataSource *dataSource = [[RKManagedObjectMappingOperationDataSource alloc] initWithManagedObjectContext:managedObjectStore.mainQueueManagedObjectContext cache:nil];
+    operation.dataSource = dataSource;
+    NSError *error = nil;
+    [operation performMapping:&error];
+    
+    assertThat(human.mutableFavoriteColors, is(equalTo(@[ @"Blue", @"Red" ])));
+    assertThat(human.mutableFavoriteColors, is(instanceOf([NSMutableArray class])));
+}
+
 @end

Tests/Models/RKHuman.h

@@ -33,6 +33,7 @@
 @property (nonatomic, strong) NSDate *createdAt;
 @property (nonatomic, strong) NSDate *updatedAt;
 @property (nonatomic, strong) NSArray *favoriteColors;
+@property (nonatomic, strong) NSMutableSet *mutableFavoriteColors;
 
 @property (nonatomic, strong) NSSet *cats;
 @property (nonatomic, strong) NSNumber *favoriteCatID;

Tests/Models/RKHuman.m

@@ -32,6 +32,7 @@
 @dynamic createdAt;
 @dynamic updatedAt;
 @dynamic favoriteColors;
+@dynamic mutableFavoriteColors;
 
 @dynamic favoriteCatID;
 @dynamic favoriteCat;