Property assertion fails when object has a field with undefined values

[gamtiq]

First of all, thank you for the excellent library!
The following assertions will fail:

expect({a: undefined}).to.have.property("a");
expect({a: undefined}).to.have.property("a", undefined);

[molnarg]

+1, having a property should be tested with if (property in object) { ... }

[devand123]

#209

[sjberry]

New chai user here. Just ran into this issue. Is this waiting on a pull request?

[charlierudolph]

Yep. #210

[yelworc]

I just fell over the inverse, i.e. I expected this to fail:
assert.notProperty({prop: undefined}, 'prop');
As far as I can see, this is covered by the PR (please correct me if I'm wrong).

[keithamus]

#210 needs to be updated, or a new PR made. @devand123 - do you have time to update #210 with the comments made?