ruby - RSpec Raising an Exception - expected exception, but nothing was raised response? -

i doing coding challenge , trying make 1 rspec test pass, unsure why code not passing. error getting after running rspec is:

1) plane#land raises error if landed failure/error: expect { plane.land }.to raise_error 'plane can not land on ground' expected exception "plane can not land on ground" nothing raised # ./spec/plane_spec.rb:22:in `block (3 levels) in '

the rspec test code is:

describe plane    let(:plane) { plane.new }  describe '#land'     'raises error if landed'       plane.land       expect { plane.land }.to raise_error 'plane can not land on ground'     end   end 

end

and main code is:

class plane    def initialize     @in_air = true   end    def land     fail "plane can not land on ground" if already_landed?     @in_air = false   end end 

i have tried substituting plane plane.new , tried using raise instead of fail , have double checked, can not see why not working.

many thanks

you haven't defined already_landed? method. means calling already_landed? raise nomethoderror: undefined method 'already_landed?' exception, never expected plane can not land... exception. , therefore expectation not pass.

just add already_landed? method model:

class plane   def initialize     @in_air = true   end    def land     fail "plane can not land on ground" if already_landed?     @in_air = false   end    def already_landed?     !@in_air   end end 

btw: makes sense newly created plane in_air? expect in_air false on initialization , need start first. change behavior:

class plane   attr_accessor :flying    def fly     # no exception here, assume save continue flying, when in air     self.flying = true   end    def land     fail 'plane can not land on ground' if landed     self.flying = false   end    def landed     !flying   end end  plane = plane.new plane.land #=> runtimeerror: plane can not land on ground