IncrementalStoreTests.m

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// ActiveResourceKitTests IncrementalStoreTests.m
//
// Copyright © 2012, Roy Ratcliffe, Pioneering Software, United Kingdom
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the “Software”), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
//  The above copyright notice and this permission notice shall be included in
//  all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED “AS IS,” WITHOUT WARRANTY OF ANY KIND, EITHER
// EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO
// EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES
// OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
//
//------------------------------------------------------------------------------

#import "IncrementalStoreTests.h"

// for ARIncrementalStore
#import "ARIncrementalStore.h"

// for ActiveResourceKitTestsBaseURL
#import "ActiveResourceKitTests.h"

@implementation IncrementalStoreTests

@synthesize context = _context;

- (NSPersistentStoreCoordinator *)coordinator
{
    return [[self context] persistentStoreCoordinator];
}

- (NSManagedObjectModel *)model
{
    return [[self coordinator] managedObjectModel];
}

/*!
 * @brief Builds a Core Data stack. @details Loads the data model, initialises
 * the coordinator with the model, adds the incremental store to the
 * coordinator, finally attaches the coordinator to a new main-queue context.
 */
- (void)setUp
{
    // Where is the data model? Does it exist in the main bundle? No. The binary
    // at /Applications/Xcode.app/Contents/Developer/Tools/otest executes the
    // tests. Instead, look for the data model within the "octest" bundle from
    // where the test launcher finds this test class.
    NSBundle *bundle = [NSBundle bundleForClass:[self class]];
    NSURL *modelURL = [bundle URLForResource:@"ActiveResourceKitTests" withExtension:@"momd"];
    NSManagedObjectModel *model = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL];
    NSPersistentStoreCoordinator *coordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:model];
    
    NSError *__autoreleasing error = nil;
    NSPersistentStore *store = [coordinator addPersistentStoreWithType:[ARIncrementalStore storeType]
                                                         configuration:nil
                                                                   URL:ActiveResourceKitTestsBaseURL()
                                                               options:nil
                                                                 error:&error];
    STAssertNotNil(store, nil);
    STAssertNil(error, nil);
    
    NSManagedObjectContext *context = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSMainQueueConcurrencyType];
    [context setPersistentStoreCoordinator:coordinator];
    [self setContext:context];
}

- (void)testPeople
{
    // Fetch all the people. Assert their non-nil names. All names are non-nil
    // including people with no names. People with no names have name equal to
    // null, where null is not exactly nil albeit equivalent depending its
    // interpretation.
    NSError *__autoreleasing error = nil;
    NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"Person"];
    NSArray *people = [[self context] executeFetchRequest:request error:&error];
    for (NSManagedObject *person in people)
    {
        NSString *name = [person valueForKey:@"name"];
        NSLog(@"person named %@", name);
    }
}

- (void)testPosts
{
    NSError *__autoreleasing error = nil;
    NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"Post"];
    NSArray *posts = [[self context] executeFetchRequest:request error:&error];
    for (NSManagedObject *post in posts)
    {
        NSString *title = [post valueForKey:@"title"];
        NSManagedObject *person = [post valueForKey:@"poster"];
        NSString *name = [person valueForKey:@"name"];
        NSLog(@"post entitled %@ by %@", title, name);
    }
}

- (void)testComments
{
    NSError *__autoreleasing error = nil;
    NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"Post"];
    NSArray *posts = [[self context] executeFetchRequest:request error:&error];
    for (NSManagedObject *post in posts)
    {
        NSString *title = [post valueForKey:@"title"];
        NSLog(@"post entitled %@", title);
        STAssertNotNil(title, nil);
        for (NSManagedObject *comment in [post valueForKey:@"comments"])
        {
            NSString *text = [comment valueForKey:@"text"];
            NSLog(@"%@", text);
            STAssertNotNil(text, nil);
        }
    }
}

- (void)testInsertAndDeletePerson
{
    NSError *__autoreleasing error = nil;
    NSManagedObject *person = [NSEntityDescription insertNewObjectForEntityForName:@"Person" inManagedObjectContext:[self context]];
    [person setValue:@"Roy Ratcliffe" forKey:@"name"];
    BOOL yes = [[self context] save:&error];
    STAssertNotNil(person, nil);
    STAssertTrue(yes, nil);
    STAssertNil(error, nil);
    
    [[self context] deleteObject:person];
    yes = [[self context] save:&error];
    STAssertTrue(yes, nil);
    STAssertNil(error, nil);
}

- (void)testUpdatePerson
{
    NSError *__autoreleasing error = nil;
    
    NSManagedObject *person = [NSEntityDescription insertNewObjectForEntityForName:@"Person" inManagedObjectContext:[self context]];
    BOOL yes = [[self context] save:&error];
    STAssertNotNil(person, nil);
    STAssertTrue(yes, nil);
    STAssertNil(error, nil);
    
    [person setValue:@"Roy Ratcliffe" forKey:@"name"];
    yes = [[self context] save:&error];
    STAssertTrue(yes, nil);
    STAssertNil(error, nil);
}

/*!
 * @brief Tests one post to many comments association
 * @details What happens when you instantiate two entities and wire them up entirely
 * at the client side first? Test it! Create a post with one
 * comment. Construct the post, comment and their relationship within the
 * client at first. Then save the context in order to transfer the objects
 * and their relationship to the remote server. Thereafter, throw away the
 * comment and refetch the comment by dereferencing the post's "comments"
 * relationship.
 */
- (void)testOnePostToManyComments
{
    NSError *__autoreleasing error = nil;
    
    NSManagedObject *post = [NSEntityDescription insertNewObjectForEntityForName:@"Post" inManagedObjectContext:[self context]];
    NSManagedObject *comment = [NSEntityDescription insertNewObjectForEntityForName:@"Comment" inManagedObjectContext:[self context]];
    STAssertNotNil(post, nil);
    STAssertNotNil(comment, nil);
    
    // Set up attributes for the post and the comment.
    [post setValue:@"De finibus bonorum et malorum" forKey:@"title"];
    [post setValue:@"Non eram nescius…" forKey:@"body"];
    [comment setValue:@"Quae cum dixisset…" forKey:@"text"];
    
    // Form the one-post-to-many-comments association.
    [comment setValue:post forKey:@"post"];
    
    // Send it all to the server.
    STAssertTrue([[self context] save:&error], nil);
    STAssertNil(error, nil);
    
    [[[[self coordinator] persistentStores] objectAtIndex:0] evictAllResources];
    [[post managedObjectContext] refreshObject:post mergeChanges:NO];
    NSMutableArray *comments = [NSMutableArray array];
    for (NSManagedObject *comment in [post valueForKey:@"comments"])
    {
        [comments addObject:[comment valueForKey:@"text"]];
    }
    STAssertFalse([comments count] == 0, nil);
    STAssertTrue([[comments objectAtIndex:0] rangeOfString:@"Quae cum dixisset…"].location != NSNotFound, nil);
}

- (void)testOnePostToManyCommentsPartiallySaved
{
    NSError *__autoreleasing error = nil;
    
    // Send the post to the server. This results in one POST request.
    NSManagedObject *post = [NSEntityDescription insertNewObjectForEntityForName:@"Post" inManagedObjectContext:[self context]];
    [post setValue:@"title" forKey:@"title"];
    [post setValue:@"body" forKey:@"body"];
    STAssertNotNil(post, nil);
    STAssertTrue([[self context] save:&error], nil);
    STAssertNil(error, nil);
    
    // Send the comment to the server. This results in a second POST request.
    NSManagedObject *comment = [NSEntityDescription insertNewObjectForEntityForName:@"Comment" inManagedObjectContext:[self context]];
    [comment setValue:@"text" forKey:@"text"];
    STAssertNotNil(comment, nil);
    STAssertTrue([[self context] save:&error], nil);
    STAssertNil(error, nil);
    
    // Send the relationship to the server. This results in a GET request
    // for the comment and for the post. This always happens because
    // insertion of objects always evicts the resource from the resource
    // cache. The server alters attributes when creating and updating. POST
    // requests therefore desynchronise server and client. Core Data then
    // asks for all the post's comments, another GET request. Finally, a PUT
    // request for the comment saves the new association.
    //
    // As a side effect, an unwanted one, Core Data also marks the post as
    // modified and issues an update for it.
    [comment setValue:post forKey:@"post"];
    STAssertTrue([[self context] save:&error], nil);
    STAssertNil(error, nil);
    
    [[[[self coordinator] persistentStores] objectAtIndex:0] evictAllResources];
    [[post managedObjectContext] refreshObject:post mergeChanges:NO];
    NSMutableArray *comments = [NSMutableArray array];
    for (NSManagedObject *comment in [post valueForKey:@"comments"])
    {
        // Assert that the comment's "post relationship" references back to the
        // post. This would fail if the relationship resolver only searches
        // attributes for the post identifier, because loading attributes splits
        // off the prefix parameters which, in this case, include the post
        // identifier (post_id). Prefix parameters live in the prefix options,
        // rather than the attributes. Such play a special role. They carry the
        // substitution values for the resource's prefix parameters.
        NSManagedObject *commentPost = [comment valueForKey:@"post"];
        STAssertEqualObjects(post, commentPost, nil);
        
        [comments addObject:[comment valueForKey:@"text"]];
    }
    STAssertFalse([comments count] == 0, nil);
    STAssertTrue([[comments objectAtIndex:0] rangeOfString:@"text"].location != NSNotFound, nil);
}

/*!
 * @brief Tests resource attributes carrying NSNull values.
 * @details Nulls become nils within managed objects. All missing properties
 * within managed objects become nils when accessed. The following tests that
 * the nulls within resources become nils when manifested by Core Data.
 */
- (void)testOnePostToManyCommentsPartiallySavedAndNullAttributes
{
    NSError *__autoreleasing error = nil;
    
    NSManagedObject *post = [NSEntityDescription insertNewObjectForEntityForName:@"Post" inManagedObjectContext:[self context]];
    STAssertNotNil(post, nil);
    STAssertTrue([[self context] save:&error], nil);
    STAssertNil(error, nil);
    
    NSManagedObject *comment = [NSEntityDescription insertNewObjectForEntityForName:@"Comment" inManagedObjectContext:[self context]];
    STAssertNotNil(comment, nil);
    STAssertTrue([[self context] save:&error], nil);
    STAssertNil(error, nil);
    
    [comment setValue:post forKey:@"post"];
    STAssertTrue([[self context] save:&error], nil);
    STAssertNil(error, nil);
    
    [[[[self coordinator] persistentStores] objectAtIndex:0] evictAllResources];
    [[post managedObjectContext] refreshObject:post mergeChanges:NO];
    NSMutableArray *comments = [NSMutableArray array];
    for (NSManagedObject *comment in [post valueForKey:@"comments"])
    {
        NSString *text = [comment valueForKey:@"text"];
        if (text)
        {
            [comments addObject:text];
        }
        STAssertNil(text, nil);
        
        // The comment has no text (nil) but it does have a valid back reference.
        NSManagedObject *commentPost = [comment valueForKey:@"post"];
        STAssertEqualObjects(post, commentPost, nil);
    }
    STAssertTrue([comments count] == 0, nil);
}

@end