expect(sum_all([1, 2, 3])).to eq 6 NoMethodError: undefined method `sum_all’ for #<RSpec::ExampleGroups::SumAll:0x007f8d5fa49270> # calc.rb:5:in `block (2 levels) in <main>' Finished in 0.00052 seconds (files took 0.09426 seconds to load) 1 example, 1 failure