fails:File.absolute_path returns the argument if it's an absolute pathname
fails:File.absolute_path resolves paths relative to the current working directory
fails:File.absolute_path does not expand '~' to a home directory.
fails:File.absolute_path does not expand '~user' to a home directory.
fails:File.absolute_path accepts a second argument of a directory from which to resolve the path
fails:File.absolute_path calls #to_path on its argument
