Skip to content

Instantly share code, notes, and snippets.

@chrismdp

chrismdp/checkout.rb

Last active March 7, 2017 11:53
Show Gist options

  • Select an option

    Learn more about clone URLs
  • Save chrismdp/c18ba9e2c4fdb43499a76a63ad0f2e62 to your computer and use it in GitHub Desktop.

Select an option

Learn more about clone URLs
Save chrismdp/c18ba9e2c4fdb43499a76a63ad0f2e62 to your computer and use it in GitHub Desktop.
Download ZIP

Revisions

  1. chrismdp renamed this gist Mar 7, 2017. 1 changed file with 0 additions and 0 deletions.
    0 - → checkout.rb
    View file
    File renamed without changes.
  2. chrismdp created this gist Mar 7, 2017.
    71 changes: 71 additions & 0 deletions -
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,71 @@
    def assert_equal(expected, actual)
    print expected == actual ? "." : "Expected #{expected.inspect} but got #{actual.inspect}\n"
    end

    class SummingRule
    def initialize(item, price)
    @item = item
    @price = price
    end

    def apply(basket)
    basket.count(@item) * @price
    end
    end

    class DiscountRule
    def initialize(item, count, discount)
    @item = item
    @count = count
    @discount = discount
    end

    def apply(basket)
    (basket.count(@item) / @count) * -@discount
    end
    end

    class Checkout
    def initialize
    @basket = []
    @rules = [
    SummingRule.new("A", 50),
    SummingRule.new("B", 30),
    DiscountRule.new("A", 3, 20),
    DiscountRule.new("B", 2, 15)
    ]
    end

    def total
    total = 0
    @rules.each do |rule|
    total += rule.apply(@basket)
    end
    total
    end

    def scan(item)
    @basket.push(item)
    end
    end

    checkout = Checkout.new
    assert_equal(0, checkout.total)
    checkout.scan("A")
    assert_equal(50, checkout.total)
    checkout.scan("B")
    assert_equal(80, checkout.total)

    checkout = Checkout.new
    checkout.scan("A")
    checkout.scan("A")
    checkout.scan("A")
    assert_equal(130, checkout.total)

    checkout = Checkout.new
    checkout.scan("B")
    checkout.scan("B")
    assert_equal(45, checkout.total)


    puts