Ruby with Rspec - How is this test passing?

Question

This test passes validations, but how?

#Rspec 
it "handles a case with an answer > 1 distance to the left" do
  nearest_larger([8,2,4,3], 2).should == 0
end

#Function
def nearest_larger(arr, idx)
  diff = 1

  loop do
    left  = idx - diff
    right = idx + diff

    if (left >= 0) && (arr[left] > arr[idx])
      return left 
    elsif (right < arr.length) && (arr[right] > arr[idx])
      return right 
    elsif (left > 0) && (right >= arr.length)
      return nil
    end

  diff += 1
  end
end

I'm working through some ruby examples and I can't understand how this test passes validation. Where is 0 being returned from?

Answer 1

When idx is 2 and diff is 2 (that is, on your second loop), left is 2 - 2 = 0 , and arr[0] == 8 , which is greater than arr[2] == 4 . The function then returns left , which is zero.