Rspec fails with “bad value for range”

问题

My method:

def swap (order)
   order = order == 'asc' ? 'desc' : 'asc'
end

Spec:

let(:order) { 'wrong_order'}

it 'swaps the order' do
 expect(swap(order)).to eq('asc')
end

This rspec is failing with the message ArgumentError: bad value for range

But if i pass 'desc' or 'asc' and change the expect it works fine.

Also i tried this on irb with just passing swap(' ') it gives me 'asc' not sure why rspec is failing

回答1:

Try being a bit more explicit with the test:

let(:order) { 'wrong_order'}

it 'swaps the order' do
  swapped_order = swap(order)

  expect(swapped_order).to eq('asc')
end

来源：https://stackoverflow.com/questions/20200655/rspec-fails-with-bad-value-for-range