Question

我正在为更大的iOS应用程序编写Core Data ContextManager。 ContextManager提供了一个NSManagedContext，当其他ContextManagers将其NSMangedContext保存到持久数据存储时，它会自动更新。

我有一个单元测试（TestContextManager），它创建两个上下文，将一个对象添加到一个，并测试以查看该对象是否出现在另一个上下文中。它没有。 为什么最后一次测试失败？

这是ContextManager的代码和失败的单元测试。单元测试中的最后一个断言失败。每一个断言传递。如您所见，ContextManager依赖于从不同的ContextManager获取更改通知并使用mergeChangesFromContextDidSaveNotification更新自身。请注意，所有内容都发生在此测试的同一个线程上。

我知道正在发送和接收NSManagedObjectContextDidSaveNotification。我知道NSManagedObjectContextDidSaveNotification在其userInfo字典中有正确的数据。

我还使用SQLite持久存储在实际设备上运行此单元测试作为应用程序测试 - 相同的断言失败。

提前致谢！

ContextManager：

#import "ContextManager.h"

@implementation ContextManager

@synthesize context;

#pragma mark - Custom code
- (void)save {

    NSError *error = nil;
    if (self.context != nil) {
        if ([self.context hasChanges] && ![self.context save:&error]) {

            NSAssert1(FALSE, @"Unable to save the managed object context.  UserInfo:\n%@", [error userInfo]);

        } 
    }

    return;
}

- (void)mergeChanges:(NSNotification *)notification {

    if (notification.object != self.context) {

        [self.context mergeChangesFromContextDidSaveNotification:notification];

    }

    return;
}

#pragma mark - Overridden NSObject methods
#pragma mark Creating, copying, and deallocating object
- (id)initWithPersistentStoreCoordinator:(NSPersistentStoreCoordinator *)persistentStoreCoordinator {

    self = [super init];

    if (self) {
        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(mergeChanges:) name:NSManagedObjectContextDidSaveNotification object:nil];
        self.context = [[[NSManagedObjectContext alloc] init] autorelease];
        [self.context setPersistentStoreCoordinator:persistentStoreCoordinator];
    }

    return self;
}

- (void)dealloc {

    [context release];
    [super dealloc];
    return;
}

@end

TestContextManager来：

#import "TestContextManager.h"
#import "ContextManager.h"
#import "CoreDataManager.h"

#define TEST_MANAGED_OBJECT @"AManagedObject"

@implementation TestContextManager

- (void)testContextManager {

    CoreDataManager *coreDataManager = [[CoreDataManager alloc] init];
    coreDataManager.storeType = NSInMemoryStoreType;

    ContextManager *contextManagerA = [coreDataManager provideContextManager];
    if (!contextManagerA) STFail(@"CoreDataManager did not provide a context manager.");

    NSManagedObjectContext *contextA = contextManagerA.context;
    if (!contextA) STFail(@"ContextManager did not provide a managed object context.");

    // setA1 has 0 objects (or whatever is initially there).
    NSSet *setA1 = [contextManagerA.context registeredObjects];
    [NSEntityDescription insertNewObjectForEntityForName:TEST_MANAGED_OBJECT inManagedObjectContext:contextManagerA.context];

    // setA2 has 1 object.
    NSSet *setA2 = [contextManagerA.context registeredObjects];
    STAssertTrue([setA2 count] == [setA1 count]+1, @"Context provided by ContextManager is not accepting new objects.");
    [contextManagerA save];

    ContextManager *contextManagerB = [coreDataManager provideContextManager];
    [NSEntityDescription insertNewObjectForEntityForName:TEST_MANAGED_OBJECT inManagedObjectContext:contextManagerB.context];     
    [contextManagerB save];

    NSSet *setA3 = [contextManagerA.context registeredObjects];

    // setA3 should have 2 objects <=== THIS TEST FAILS
    STAssertTrue([setA3 count] == [setA1 count]+2, @"Context is not updating new objects.");

    [coreDataManager release];    


    return;
}

@end

Answer 1

您是否实际设置了ContextManager来观察保存managedObjectContext的通知？你没有在这里展示，所以我只想介绍最简单的案例。

抱歉，我应该对Erik的帖子发表评论。

Answer 2

感谢您回答我的问题鲜为人知。显然，我需要阅读registeredObjects实际返回的内容。我想这里的好消息是实际代码有效 - 单元测试很糟糕......

这是正确测试被测单位并通过的单元测试：

#import "TestContextManager.h"
#import "ContextManager.h"
#import "CoreDataManager.h"

#define TEST_MANAGED_OBJECT @"AManagedObject"

@implementation TestContextManager

- (void)testContextManager {

    CoreDataManager *coreDataManager = [[CoreDataManager alloc] init];
    coreDataManager.storeType = NSInMemoryStoreType;

    ContextManager *contextManagerA = [coreDataManager provideContextManager];
    if (!contextManagerA) STFail(@"CoreDataManager did not provide a context manager.");

    NSManagedObjectContext *contextA = contextManagerA.context;
    if (!contextA) STFail(@"ContextManager did not provide a managed object context.");

    NSEntityDescription *entityDescriptionA = [NSEntityDescription entityForName:TEST_MANAGED_OBJECT inManagedObjectContext:contextA];

    // make A1 request on an empty context (0 objects)
    NSFetchRequest *requestA1 = [[NSFetchRequest alloc] init];
    [requestA1 setEntity:entityDescriptionA];
    NSError *errorA1 = nil;
    NSArray *arrayA1 = [contextA executeFetchRequest:requestA1 error:&errorA1];
    if (arrayA1 == nil) STFail(@"Fetch request A1 failed.");
    if ([arrayA1 count] != 0) STFail(@"Context A1 is not empty at start of test.");

    // add an object to context A and make request A2
    [NSEntityDescription insertNewObjectForEntityForName:TEST_MANAGED_OBJECT inManagedObjectContext:contextManagerA.context];
    NSFetchRequest *requestA2 = [[NSFetchRequest alloc] init];
    [requestA2 setEntity:entityDescriptionA];
    NSError *errorA2 = nil;
    NSArray *arrayA2 = [contextA executeFetchRequest:requestA2 error:&errorA2];
    if (arrayA2 == nil) STFail(@"Fetch request A2 failed.");
    if ([arrayA2 count] != 1) STFail(@"Context A2 did not successfully add an object.");

    // add an object to context B and make request B1
    ContextManager *contextManagerB = [coreDataManager provideContextManager];
    NSManagedObjectContext *contextB = contextManagerB.context;
    NSEntityDescription *entityDescriptionB = [NSEntityDescription entityForName:TEST_MANAGED_OBJECT inManagedObjectContext:contextB];
    [NSEntityDescription insertNewObjectForEntityForName:TEST_MANAGED_OBJECT inManagedObjectContext:contextManagerB.context]; 
    NSFetchRequest *requestB1 = [[NSFetchRequest alloc] init];
    [requestB1 setEntity:entityDescriptionB];
    NSError *errorB1 = nil;
    NSArray *arrayB1 = [contextB executeFetchRequest:requestB1 error:&errorB1];
    if (arrayB1 == nil) STFail(@"Fetch request B1 failed.");
    if ([arrayB1 count] != 1) STFail(@"Context B1 did not successfully add an object.");

    // save contextB
    [contextManagerB save];

    // check if contextA was updated
    NSFetchRequest *requestA3 = [[NSFetchRequest alloc] init];
    [requestA3 setEntity:entityDescriptionA];
    NSError *errorA3 = nil;
    NSArray *arrayA3 = [contextA executeFetchRequest:requestA3 error:&errorA3];
    if (arrayA3 == nil) STFail(@"Fetch request A3 failed.");
    if ([arrayA3 count] != 2) STFail(@"Context A did not update correctly.");

    [requestA1 release];
    [requestA2 release];
    [requestB1 release];
    [requestA3 release];
    [coreDataManager release];    

    return;
}

@end

核心数据mergeChangesFromContextDidSaveNotification不起作用

2 个答案: