Fixed.

undefined method `are_you_playing_banjo'

Tests are wrong in Ruby. It should be:

Test.assert_equals(are_you_playing_banjo("Adam"), "Adam does not play banjo")
Test.assert_equals(are_you_playing_banjo("Paul"), "Paul does not play banjo")
Test.assert_equals(are_you_playing_banjo("Ringo"), "Ringo plays banjo");
Test.assert_equals(are_you_playing_banjo("bravo"), "bravo does not play banjo")
Test.assert_equals(are_you_playing_banjo("rolf"), "rolf plays banjo")