Core-data with SenTestCase class : unexpected error - ios

Question

I am working on an application which stores and retrieves data from sqlite db, using core data. For this I have created a separate class which acts like a data link layer - LocalDBController
Below is the implementation of one of its methods- selectAddressWithAddressId:
- (NSDictionary *)selectAddressWithAddressId:(NSString *)addressId
{
NSDictionary *dictToReturn = nil;
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"address_id == %#",addressId];
NSEntityDescription *entityDescription = [NSEntityDescription entityForName:#"Address" inManagedObjectContext:self.moc]; // returning nil when invoked from test case class
NSFetchRequest *request = [[NSFetchRequest alloc] init];
[request setEntity:entityDescription];
[request setPredicate:predicate];
NSError *err = nil;
NSArray *array = [self.moc executeFetchRequest:request error:&err];
// some more code...
return dictToReturn;
}
Now I am trying to implement a test case class for it (SenTestCase class).
I have written below init method in LocalDBController class, so that it uses the default persistent store if value of environment variable is 'Run' and uses in-memory persistent store if value of environment variable is 'Test':
- (id)init
{
if (self = [super init]) {
// initializing moc based on if run setting is used or test is used
if ([[[[NSProcessInfo processInfo] environment] objectForKey:#"TARGET"] isEqualToString:#"TEST"]) {
NSManagedObjectModel *mom = [NSManagedObjectModel mergedModelFromBundles:nil];
NSPersistentStoreCoordinator *psc = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:mom];
[psc addPersistentStoreWithType:NSInMemoryStoreType configuration:nil URL:nil options:nil error:NULL];
self.moc = [[NSManagedObjectContext alloc] init];
self.moc.persistentStoreCoordinator = psc;
}
else
{
self.moc = [(AppDelegate *)[[UIApplication sharedApplication] delegate] managedObjectContext];
}
}
return self;
}
In my test class I am trying to invoke below method:
STAssertNotNil([self.localDBController selectAddressWithAddressId:#"123"], #"No data found");
Problem is-
In this case, value of entityDescription obtained in selectAddressWithAddressId: method is nil, though the value of self.moc is not nil. So it
is throwing this exception msg in console: raised
executeFetchRequest:error: A fetch request must have an entity..
If I execute the above method from the class which is not included in my test case bundle, say appDelegate, it works fine.
Can anyone suggest me if I am doing anything wrong in it?