isMemberOfClass doesn't work as expected with ocunit

Question

Possible Duplicate:
'isMemberOfClass' returning 'NO' when custom init

I've some trouble with the "isMemberOfClass"-Method.

I have a class, that generates and returns objects ("MyObject")

// ObjectFactory.h
...
-(MyObject*)generateMyObject;
...

// ObjectFactory.m
...
-(MyObject*)generateMyObject
{
    MyObject *obj = [[MyObject alloc]init];
    obj.name = @"Whatever";      // set properties of object
    return obj;
}
...

And there's a unittest-class, that calls the generateMyObject-selector and checks the class of the returned object:

...
ObjectFactory *factory = [[ObjectFactory alloc]init];
MyObject *obj = [factory generateMyObject];
if (![obj isMemeberOfclass:[MyObject class]])
    STFail(@"Upps, object of wrong class returned...");
else
...

I expect, that the else-part is processed...but the STFail(...) is called instead, but why?

Thx for any help! Regards, matrau

Ok, here is the original copy&pasted code:

//testcase
- (void)test001_setCostumeFirstCostume
{
    NSString *xmlString = @"<Bricks.SetCostumeBrick><costumeData reference=\"../../../../../costumeDataList/Common.CostumeData\"/><sprite reference=\"../../../../..\"/></Bricks.SetCostumeBrick>";
    NSError *error;
    NSData *xmlData = [xmlString dataUsingEncoding:NSASCIIStringEncoding];
    GDataXMLDocument *doc = [[GDataXMLDocument alloc] initWithData:xmlData
                                                           options:0 error:&error];
    SetCostumeBrick *newBrick = [self.parser loadSetCostumeBrick:doc.rootElement];
    if (![newBrick isMemberOfClass:[SetCostumeBrick class]])
        STFail(@"Wrong class-member");
}

// "MyObject"
@implementation SetCostumeBrick
@synthesize indexOfCostumeInArray = _indexOfCostumeInArray;

- (void)performOnSprite:(Sprite *)sprite fromScript:(Script*)script
{
    NSLog(@"Performing: %@", self.description);

    [sprite performSelectorOnMainThread:@selector(changeCostume:) withObject:self.indexOfCostumeInArray waitUntilDone:true];
}

- (NSString*)description
{
    return [NSString stringWithFormat:@"SetCostumeBrick (CostumeIndex: %d)", self.indexOfCostumeInArray.intValue];
}

@end

// superclass of SetCostumeBrick
@implementation Brick
- (NSString*)description
{
    return @"Brick (NO SPECIFIC DESCRIPTION GIVEN! OVERRIDE THE DESCRIPTION METHOD!";
}

//abstract method (!!!)
- (void)performOnSprite:(Sprite *)sprite fromScript:(Script*)script
{
    @throw [NSException exceptionWithName:NSInternalInconsistencyException
                                   reason:[NSString stringWithFormat:@"You must override %@ in a subclass", NSStringFromSelector(_cmd)]
                                 userInfo:nil];
}
@end

// the "factory" (a xml-parser)
- (SetCostumeBrick*)loadSetCostumeBrick:(GDataXMLElement*)gDataSetCostumeBrick
{
    SetCostumeBrick *ret = [[SetCostumeBrick alloc] init];

    NSArray *references = [gDataSetCostumeBrick elementsForName:@"costumeData"];
    GDataXMLNode *temp = [(GDataXMLElement*)[references objectAtIndex:0]attributeForName:@"reference"];
    NSString *referencePath = temp.stringValue;

    if ([referencePath length] > 2)
    {
        if([referencePath hasSuffix:@"]"]) //index found
        {
            NSString *indexString = [referencePath substringWithRange:NSMakeRange([referencePath length]-2, 1)];
            ret.indexOfCostumeInArray = [NSNumber numberWithInt:indexString.intValue-1];
        }
        else 
        {
            ret.indexOfCostumeInArray = [NSNumber numberWithInt:0];
        }
    }
    else 
    {
        ret.indexOfCostumeInArray = nil;
        @throw [NSException exceptionWithName:NSInternalInconsistencyException
                                       reason:[NSString stringWithFormat:@"Parser error! (#1)"]
                                     userInfo:nil];
    }

    NSLog(@"Index: %@, Reference: %@", ret.indexOfCostumeInArray, [references objectAtIndex:0]);

    return ret;
}

SOLUTION:

Eiko/jrturton gave me a link to the solution - thx: isMemberOfClass returns no when ViewController is instantiated from UIStoryboard

The problem was, that the classes were included in both targets (app and test bundle)

Thank you guys for your help :)

Please use copy-paste... that code has obvious spelling mistakes in method names. — Eiko, Oct 03 '12 at 15:51
Can you show the `init` method of the `MyObject` class? Does it actually return a `MyObject` or perhaps some subclass instance? — Martin R, Oct 03 '12 at 15:59
Ok, sry, I'll copy&paste next time... there's no explicit init-method (is this the issue??) — matrau, Oct 03 '12 at 16:17
debug-result (@if-line): (lldb) po [obj class] (id) $1 = 0x00066968 MyObject — matrau, Oct 03 '12 at 16:21
Please show the output of `[newBrick class]` and `[SetCostumeBrick class]`. — Martin R, Oct 03 '12 at 16:50
[newBrick class] => 'SetCostumeBrick' [SetCostumeBrick class] => 'SetCostumeBrick' — matrau, Oct 03 '12 at 16:53
Very strange ... or I am blind and miss the obvious. Can you show the debugger output of "po [newBrick class]" and "po [SetCostumeBrick class]", including the addresses? — Martin R, Oct 03 '12 at 17:42
(lldb) po [newBrick class] (id) $1 = 0x00066a84 SetCostumeBrick — matrau, Oct 03 '12 at 17:47
(lldb) po [SetCostumeBrick class] (id) $2 = 0x00066a84 SetCostumeBrick — matrau, Oct 03 '12 at 17:48
What's the debugger say about isMemberOfClass and isKindOfClass on those? — Jody Hagins, Oct 03 '12 at 17:49
[newBrick class] => '0x66a84' [SetCostumeBrick class] => '0x7aaf82c' — matrau, Oct 03 '12 at 17:50
Aha! Was that from printing %p (the comment I deleted because the debugger seemed to indicate it was useless)? — Jody Hagins, Oct 03 '12 at 17:51
Are you using KVO, or anything else that may be doing IsA-swizzling? — Jody Hagins, Oct 03 '12 at 17:52
What about this? `NSLog(@"className: %s", class_getName([newBrick class]);` — Jody Hagins, Oct 03 '12 at 17:56
no KVO - I don't think so..........Output: className: SetCostumeBrick — matrau, Oct 03 '12 at 17:58
I am also confused. `[SetCostumeBrick class]` is 0x00066a84 in one comment and 0x7aaf82c in another comment. — Martin R, Oct 03 '12 at 18:37
"else" is "do nothing, unit-test is ok... there is no explicit else-part................0x7aaf834 is the output of NSLog(@"%p", [SetCostumeBrick class]); ........ 0x00066a84 is the debugger-output of "po [SetCostumeBrick class]" — matrau, Oct 03 '12 at 18:45
You're right jrturton, I found the solution there => http://stackoverflow.com/questions/11675256/ismemberofclass-returns-no-when-viewcontroller-is-instantiated-from-uistoryboard Thanks to all for your help :) — matrau, Oct 03 '12 at 19:14

score 2 · Answer 1 · edited Oct 03 '12 at 16:25

2

You generally want isKindOfClass:, not isMemberOfClass. The isKindOfClass: will return YES if the receiver is a member of a subclass of the class in question, whereas isMemberOfClass: will return NO in the same case.

if ([obj isKindOfClass:[MyObject class]])

For example,

NSArray *array = [NSArray array];

Here [array isMemberOfClass:[NSArray class]] will return NO but [array isKindOfClass:[NSArray class]] will return YES.

edited Oct 03 '12 at 16:25

Mick MacCallum

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answered Oct 03 '12 at 15:51

Paresh Masani

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That's wrong. isKindOfClass tests with subclasses as well, and here clearly isMemberOfClass should work as well. – Eiko Oct 03 '12 at 15:53
That's true but I thought the sub-classing might be the issue. Added details. – Paresh Masani Oct 03 '12 at 16:05
`init` methods need not return `self`, they can return some other object, e.g. an instance of a subclass. We don't know if that is the case here, but if it is, applefreak has given the right answer. – Martin R Oct 03 '12 at 16:21
@Eiko In the case of `NSArray` the method `isMemberOfClass` returns NO because of the class cluster. For me, `NSLog(@"%@", [array class])` returns `__NSArrayI` which is not `NSArray`. Therefore, `isMemberOfClass` returns NO, whereas `isKindOfClass` returns YES. I think this is a distraction from the OPs question though as their MyObject class is unlikely to be a class cluster so `isMemberOfClass` should work. – mttrb Oct 03 '12 at 16:21
@mttrb I know all the details, and for this specific question the answer just doesn't make sense. It's perfectly fine to suggest isKindOfClass: as a comment, but as it cannot solve the problem, it is no answer. – Eiko Oct 03 '12 at 16:27
@Eiko I misunderstood your original comment. I read "and here clearly iMemberOfClass should work" as referring to this answer not to the OP's original question. – mttrb Oct 04 '12 at 01:55

score 0 · Accepted Answer · edited May 23 '17 at 11:48

0

Ok, with different class addresses per your comment, I think I can track this down to be a duplicate of this:

isMemberOfClass returns no when ViewController is instantiated from UIStoryboard

Basically, your class is included twice.

edited May 23 '17 at 11:48

Community

1
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answered Oct 03 '12 at 19:00

Eiko

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This should be a close as duplicate vote, not an answer. – jrturton Oct 03 '12 at 19:03
@jrurton I thought so as well at first, but then, there is more "debugging information" in this post than in the other - hence I think this question should receive a proper answer (which obviously links back to the longer original answer). – Eiko Oct 03 '12 at 19:06

isMemberOfClass doesn't work as expected with ocunit

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