{"issue":{"state":"open","pull_request":{"diff_url":null,"html_url":null,"patch_url":null},"milestone":null,"user":{"avatar_url":"https://secure.gravatar.com/avatar/7613fb4886bd0155fe1f553f6509d876?d=https://a248.e.akamai.net/assets.github.com%2Fimages%2Fgravatars%2Fgravatar-140.png","gravatar_id":"7613fb4886bd0155fe1f553f6509d876","url":"https://api.github.com/users/davisp","login":"davisp","id":19929},"assignee":null,"updated_at":"2011-11-16T21:49:59Z","labels":[],"closed_at":null,"comments":3,"url":"https://api.github.com/repos/manopapad/proper/issues/21","body":"Unless I'm completely misunderstanding how post conditions are supposed to work, this appears to be a bug in passing the old state to the postcondition function:\r\n\r\n    https://github.com/manopapad/proper/blob/master/src/proper_statem.erl#L537\r\n\r\nSeems like it should really be using State2 from line 534.","html_url":"https://github.com/manopapad/proper/issues/21","title":"Bug updating state for statem post conditions","number":21,"id":2224717,"created_at":"2011-11-14T03:25:04Z"},"action":"created","comment":{"user":{"avatar_url":"https://secure.gravatar.com/avatar/751b79b5942b059fbecff0b1ab32ad48?d=https://a248.e.akamai.net/assets.github.com%2Fimages%2Fgravatars%2Fgravatar-140.png","gravatar_id":"751b79b5942b059fbecff0b1ab32ad48","url":"https://api.github.com/users/EiriniArvaniti","login":"EiriniArvaniti","id":422347},"updated_at":"2011-11-16T21:49:59Z","url":"https://api.github.com/repos/manopapad/proper/issues/comments/2768507","body":"\r\nI see what you mean, your assumption is reasonable. But then, it is also reasonable that you may want to check the Result of a call, given the context (i.e. state) in which that call was performed, not given the resulting state.\r\nSo in our approach, we assume that an error will be detected  as an unexpected result of a call. Even if this is not captured\r\nby a false postcondition right after the call, chances are high that it will become obvious sooner or later because of some state inconsistency. And then shrinking helps you identify it.","id":2768507,"created_at":"2011-11-16T21:49:59Z"}}