Correct nil should equal(nil) checking

[Paul Taykalo]

Case 1

nil should equal(nil)
Result : Succeeds, since nil has integer type

Case 2

obj.stringPropery = nil
obj2.stringPropery = nil
...
obj.stringPropery should equal(obj2.stringPropery)

Result : Fails, since Equal comparator
https://github.com/pivotal/cedar/blob/master/Source/Headers/Matchers/Comparators/CompareEqual.h#L9
will transform it [nil isEqual:nil]

Proposed solution

Add by-reference check for objects

return [actualValueId nonretainedObjectValue] == [expectedValueId nonretainedObjectValue] || [[actualValueId nonretainedObjectValue] isEqual:[expectedValueId nonretainedObjectValue]];

OR

return ([actualValueId nonretainedObjectValue] == nil && [expectedValueId nonretainedObjectValue] == nil) || 
       ([[actualValueId nonretainedObjectValue] isEqual:[expectedValueId nonretainedObjectValue]]);

[Sam Coward]

Thanks for picking this up and reporting it. I've just pushed a fix for this to master @c7ae8bc9

[Sam Coward]

We ended up reverting this change. The old behavior is more effective at driving out implementations with fewer tests. If you explicitly expect values to be nil then there is always the be_nil matcher.