require File.expand_path('../../../spec_helper', __FILE__)
require File.expand_path('../fixtures/classes', __FILE__)

describe "Array#product" do
  it "returns converted arguments using :to_ary" do
    lambda{ [1].product(2..3) }.should raise_error(TypeError)
    ar = ArraySpecs::ArrayConvertable.new(2,3)
    [1].product(ar).should == [[1,2],[1,3]]
    ar.called.should == :to_ary
  end

  it "returns the expected result" do
    [1,2].product([3,4,5],[6,8]).should == [[1, 3, 6], [1, 3, 8], [1, 4, 6], [1, 4, 8], [1, 5, 6], [1, 5, 8],
                                            [2, 3, 6], [2, 3, 8], [2, 4, 6], [2, 4, 8], [2, 5, 6], [2, 5, 8]]
  end

  it "has no required argument" do
    [1,2].product.should == [[1],[2]]
  end

  it "returns an empty array when the argument is an empty array" do
    [1, 2].product([]).should == []
  end

  it "does not attempt to produce an unreasonable number of products" do
    a = (0..100).to_a
    lambda do
      a.product(a, a, a, a, a, a, a, a, a, a)
    end.should raise_error(RangeError)
  end

  describe "when given a block" do
    it "yields all combinations in turn" do
      acc = []
      [1,2].product([3,4,5],[6,8]){|array| acc << array}
      acc.should == [[1, 3, 6], [1, 3, 8], [1, 4, 6], [1, 4, 8], [1, 5, 6], [1, 5, 8],
                     [2, 3, 6], [2, 3, 8], [2, 4, 6], [2, 4, 8], [2, 5, 6], [2, 5, 8]]

      acc = []
      [1,2].product([3,4,5],[],[6,8]){|array| acc << array}
      acc.should be_empty
    end

    it "will ignore unreasonable numbers of products and yield anyway" do
      a = (0..100).to_a
      lambda do
        a.product(a, a, a, a, a, a, a, a, a, a)
      end.should raise_error(RangeError)
    end
  end

  describe "when given an empty block" do
    it "returns self" do
      arr = [1,2]
      arr.product([3,4,5],[6,8]){}.should equal(arr)
      arr = []
      arr.product([3,4,5],[6,8]){}.should equal(arr)
      arr = [1,2]
      arr.product([]){}.should equal(arr)
    end
  end
end
