require 'spec_helper'

describe Immutable::Set do
  [:reject, :delete_if].each do |method|
    describe "##{method}" do
      let(:set) { S['A', 'B', 'C'] }

      context 'when nothing matches' do
        it 'returns self' do
          set.send(method) { |item| false }.should equal(set)
        end
      end

      context 'when only some things match' do
        context 'with a block' do
          let(:result) { set.send(method) { |item| item == 'A' }}

          it 'preserves the original' do
            result
            set.should eql(S['A', 'B', 'C'])
          end

          it 'returns a set with the matching values' do
            result.should eql(S['B', 'C'])
          end
        end

        context 'with no block' do
          it 'returns self' do
            set.send(method).class.should be(Enumerator)
            set.send(method).each { |item| item == 'A' }.should == S['B', 'C']
          end
        end
      end

      context 'on a large set, with many combinations of input' do
        it 'still works' do
          array = (1..1000).to_a
          set   = S.new(array)
          [0, 10, 100, 200, 500, 800, 900, 999, 1000].each do |threshold|
            result = set.send(method) { |item| item > threshold }
            result.size.should == threshold
            1.upto(threshold)  { |n| result.include?(n).should == true }
            (threshold+1).upto(1000) { |n| result.include?(n).should == false }
          end
        end
      end
    end
  end
end
