require 'spec_helper'

describe AutoIncrement::Incrementor do
  {
    nil => 1, 0 => 1, 1 => 2, 'A' => 'B', 'Z' => 'AA', 'AA' => 'AB', 'AAAAA' => 'AAAAB'
  }.each do |previous_value, next_value|
    describe "increment value for #{previous_value}" do
      it {
        allow(subject).to receive(:maximum) { previous_value }
        expect(subject.send(:increment)).to eq next_value
      }
    end
  end

  describe "initial value of string" do
    subject {
      AutoIncrement::Incrementor.new initial: 'A'
    }

    it {
      allow(subject).to receive(:maximum) { nil }
      expect(subject.send(:increment)).to eq 'A'
    }
  end
end