require 'spec_helper'

describe Immutable::List do
  [:reduce, :inject].each do |method|
    describe "##{method}" do
      context 'on a really big list' do
        it "doesn't run out of stack" do
          -> { BigList.send(method, &:+) }.should_not raise_error
        end
      end

      [
        [[], 10, 10],
        [[1], 10, 9],
        [[1, 2, 3], 10, 4],
      ].each do |values, initial, expected|
        context "on #{values.inspect}" do
          context "with an initial value of #{initial} and a block" do
            it "returns #{expected.inspect}" do
              L[*values].send(method, initial) { |memo, item| memo - item }.should == expected
            end
          end
        end
      end

      [
        [[], nil],
        [[1], 1],
        [[1, 2, 3], -4],
      ].each do |values, expected|
        context "on #{values.inspect}" do
          context 'with no initial value and a block' do
            it "returns #{expected.inspect}" do
              L[*values].send(method) { |memo, item| memo - item }.should == expected
            end
          end
        end
      end

      context 'with no block and a symbol argument' do
        it 'uses the symbol as the name of a method to reduce with' do
          L[1, 2, 3].send(method, :+).should == 6
        end
      end

      context 'with no block and a string argument' do
        it 'uses the string as the name of a method to reduce with' do
          L[1, 2, 3].send(method, '+').should == 6
        end
      end
    end
  end
end
