A "fake" (as opposed to a mock) is a pretty well understood concept. Is there a difference between a fake and a "nullable"? As far as I can tell this is a patt

A "fake" (as opposed to a mock) is a pretty well understood concept. Is there a difference between a fake and a "nullable"? As far as I can tell this is a pattern for merging your fakes and reals which seems cumbersome and error prone