Confusion with nullMock and addObserver:...

[dmeehan1968]

It's been a few months since I've had a chance to do much with Kiwi, but now getting back into it, and can't seem to make sense of the following. Am I doing something drastically wrong?

I'm trying to write a test that validates that an object has an observer added to it. in my code, I'm trying to inject a nullMock into the class being tested so that I can check that the KVO calls are being made. I started with a real instance of the observed class and this was working ok, but the automatic stubbing was causing problems elsewhere, so I wanted to adapt the tests to use mocks to simplify things.

The code below is a example of this behaviour, not from my project, but the effect is the same.

When observed is a nullMock, the addObserver expectation fails, but the addObject is correctly ignored.

When observed is a mock, the expectation passes, but then I get a failure because of the unexpected addObject (which is correct behaviour for Kiwi).

So the problem appears to be that Kiwi can't set an expectation on addObserver:forKeyPath:options:context: when using nullMocks.

NSMutableArray *observed = [NSMutableArray nullMock];
NSObject *observer = [NSObject nullMock];

[[observed should] receive:@selector(addObserver:forKeyPath:options:context:)];

[observed addObserver: observer forKeyPath:@"count" options: NSKeyValueObservingOptionNew context: nil];

[observed addObject:@1];

I get the error:

expected subject to receive -addObserver：forKeyPath：options：context： exactly 1 time, but received it 0 times

I'm using :head in my Podfile to get the latest Kiwi.

[modocache]

I believe you've exposed a bug in Kiwi's implementation. Namely, the following test fails, although I believe it should succeed:

it(@"asserts a null mock receives -addObserver:forKeyPath:options:context:", ^{
    NSObject *nullMock = [NSObject nullMock];
    [[nullMock should] receive:@selector(addObserver:forKeyPath:options:context:)];
    [nullMock addObserver:[NSObject new]
               forKeyPath:@"description"
                  options:0
                  context:nil];
});

I'll try looking into it.

[dmeehan1968]

I've worked with Kiwi mocks for KVO in the past and they seemed fine, but the nullMock is I think ignoring more than it should do. Instance methods on NSObject should probably be allowed to pass through.

[modocache]

The weird thing is that most instance methods do work. The following test passes, as expected:

it(@"asserts a null mock receives -description", ^{
    NSObject *nullMock = [NSObject nullMock];
    [[nullMock should] receive:@selector(description)];
    [nullMock description];
});

I believe the problem is specific to -addObserver:forKeyPath:options:context:.

[tkuichooseyou]

This issue comes up for me even with regular mock and not just nullMock. I realize this issue is old, sorry to disturb the peace :(