require 'spec_helper'

describe Immutable::List do
  describe '#one?' do
    context 'on a really big list' do
      it "doesn't run out of stack" do
        -> { BigList.one? { false } }.should_not raise_error
      end
    end

    context 'when empty' do
      it 'with a block returns false' do
        L.empty.one? {}.should == false
      end

      it 'with no block returns false' do
        L.empty.one?.should == false
      end
    end

    context 'when not empty' do
      context 'with a block' do
        let(:list) { L['A', 'B', 'C'] }

        it 'returns false if the block returns true more than once' do
          list.one? { |item| true }.should == false
        end

        it 'returns false if the block never returns true' do
          list.one? { |item| false }.should == false
        end

        it 'returns true if the block only returns true once' do
          list.one? { |item| item == 'A' }.should == true
        end
      end

      context 'with no block' do
        it 'returns false if more than one value is truthy' do
          L[nil, true, 'A'].one?.should == false
        end

        it 'returns true if only one value is truthy' do
          L[nil, true, false].one?.should == true
        end
      end
    end
  end
end