Hey! Click on underlined code for more options. expect { engine.start } .to change { engine.state }. from (:off). (:off). to (:on) (:on) (engine, :state). from (:off). (:off). to (:on) (:on) expect { User.create name: ‘John’ } .to change { User.count }. by 1 (User, :count). by 1 expect { post.save } .to change { post.updated_at } (post, :updated_at)

expect { raise "what the hell!" } { raise "what the hell!" } .to raise_error raise_exception raising RuntimeError, "what the hell!" /hell/ "what the hell!" RuntimeError

Be aware of using raise_error without params, since it catch ANY errors, including syntax errors