Desired assertion for testing that KVO info isn't leaked when system-under-test is dealloc'd

gistfile1.m

@interface FooKVOTests : SenTestCase
@end

@implementation FooKVOTests

#pragma mark Observation info leak regression

- (void)test_observation_info_is_not_leaked
{
    Foo *__weak foo = [Foo new]; // dealloc foo immediately

    expect(foo).to.beNil(); // ✔

    // Now assert that foo was not deallocated while key value observers were
    // still registered, i.e., I don't want to run the code and see this in the
    // log:
    //
    //   An instance 0x109552700 of class Foo was deallocated while key value
    //   observers were still registered with it. Observation info was leaked,
    //   and may even become mistakenly attached to some other object. Set a
    //   breakpoint on NSKVODeallocateBreak to stop here in the debugger.
    //   Here's the current observation info:
    //   <NSKeyValueObservationInfo 0x109564770> (
    //     <NSKeyValueObservance 0x10954a290: Observer: 0x109552700,
    //       Key path: somePath, Options: <New: NO, Old: NO, Prior: NO>
    //       Context: 0x10001ddb8, Property: 0x109644ba0>
    //   )

}

@end