long.rb

# Subject under test
class Stack
  def initialize
    @items = []
  end

  def push(item)
    @items << item
  end

  def pop
    @items.pop
  end

  def peek
    @items.last
  end

  def depth
    @items.size
  end
end

# Test
class Long < SmellTest
  def test_make_sure_everything_works
    subject = Stack.new

    # Test Push
    subject.push("A")
    subject.push("B")
    subject.push("C")

    assert_equal "C", subject.pop
    assert_equal "B", subject.pop
    assert_equal "A", subject.pop

    # Test Peek
    subject.push("D")
    subject.push("E")

    assert_equal "E", subject.peek

    subject.pop

    assert_equal "D", subject.peek

    subject.pop

    # Test Depth
    subject.push("F")
    subject.push("G")

    assert_equal 2, subject.depth

    # Test Pop
    subject.pop
    subject.pop

    assert_equal 0, subject.depth
    assert_equal nil, subject.pop
  end
end