gistfile1.m

// Core Data question...

// So I have a unit test like this:

- (void)testNewClientFromBusiness
{
	PTBusiness *business = [modelController newBusiness];
	STAssertTrue([[business clients] count] == 0, @"is actually %d", [[business clients] count]);
	PTClient *client = [business newClient];
	STAssertTrue([business isEqual:[client business]], nil);
	STAssertTrue([[business clients] count] == 1, @"is actually %d", [[business clients] count]);
}

// When I implement -newClient inside of PTBusiness like this:

- (PTClient *)newClient
{
	PTClient *client = [NSEntityDescription insertNewObjectForEntityForName:@"Client" inManagedObjectContext:[self managedObjectContext]];
	[client setBusiness:self];
	[client updateLocalDefaultsBasedOnBusiness];
	return client;
}

// The test fails cause [[business clients] count] is still 0 after -newClient is called.

// If I impliment it like this:

- (PTClient *)newClient
{
	PTClient *client = [NSEntityDescription insertNewObjectForEntityForName:@"Client" inManagedObjectContext:[self managedObjectContext]];
	NSMutableSet *group = [self mutableSetValueForKey:@"clients"];
	[group addObject:client];
	[client updateLocalDefaultsBasedOnBusiness];
	return client;
}

// The tests passes.

// So am I right in thinking the inverse relationship is only updated when I interact with the mutable set?