require 'spec_helper'

describe Immutable::List do
  describe '#grep' do
    it 'is lazy' do
      -> { Immutable.stream { fail }.grep(Object) { |item| item } }.should_not raise_error
    end

    context 'without a block' do
      [
        [[], []],
        [['A'], ['A']],
        [[1], []],
        [['A', 2, 'C'], %w[A C]],
      ].each do |values, expected|
        context "on #{values.inspect}" do
          it "returns #{expected.inspect}" do
            L[*values].grep(String).should eql(L[*expected])
          end
        end
      end
    end

    context 'with a block' do
      [
        [[], []],
        [['A'], ['a']],
        [[1], []],
        [['A', 2, 'C'], %w[a c]],
      ].each do |values, expected|
        context "on #{values.inspect}" do
          let(:list) { L[*values] }

          it 'preserves the original' do
            list.grep(String, &:downcase)
            list.should eql(L[*values])
          end

          it "returns #{expected.inspect}" do
            list.grep(String, &:downcase).should eql(L[*expected])
          end
        end
      end
    end
  end
end
