require 'spec_helper'

describe Immutable::Vector do
  describe '#drop_while' do
    [
      [[], []],
      [['A'], []],
      [%w[A B C], ['C']],
    ].each do |values, expected|
      describe "on #{values.inspect}" do
        let(:vector) { V[*values] }

        describe 'with a block' do
          let(:result) { vector.drop_while { |item| item < 'C' } }

          it 'preserves the original' do
            result
            vector.should eql(V[*values])
          end

          it "returns #{expected.inspect}" do
            result.should eql(V[*expected])
          end
        end

        describe 'without a block' do
          it 'returns an Enumerator' do
            vector.drop_while.class.should be(Enumerator)
            vector.drop_while.each { |item| item < 'C' }.should eql(V[*expected])
          end
        end
      end
    end

    context 'on an empty vector' do
      it 'returns an empty vector' do
        V.empty.drop_while { false }.should eql(V.empty)
      end
    end

    it 'returns an empty vector if block is always true' do
      V.new(1..32).drop_while { true }.should eql(V.empty)
      V.new(1..100).drop_while { true }.should eql(V.empty)
    end

    it 'stops dropping items if block returns nil' do
      V[1, 2, 3, nil, 4, 5].drop_while { |x| x }.should eql(V[nil, 4, 5])
    end

    it 'stops dropping items if block returns false' do
      V[1, 2, 3, false, 4, 5].drop_while { |x| x }.should eql(V[false, 4, 5])
    end
  end
end