test_stack-lesson24.rb

require 'test/unit'
require 'stack'

class TestStack < Test::Unit::TestCase
  def setup
    @stack = Stack.new
  end

  def test_empty?
    assert(@stack.empty?)
  end

  def test_push_pop_3
    @stack.push 3
    assert_equal(3, @stack.pop)
  end

  def test_push_pop_1
    @stack.push 1
    assert_equal(1, @stack.pop)
  end

  def test_push_pop_empty
    @stack.push 2
    assert(!@stack.empty?)
    @stack.pop
    assert(@stack.empty?)
  end

  def test_zero_pop
    assert_raise(EmptyStackError) do
      @stack.pop
    end
  end

  def test_stack_size
    @stack.push 5
    assert_equal(1, @stack.size)
  end

  def test_stack_size_2
    @stack.push 1
    @stack.push 2
    assert_equal(2, @stack.size)
  end

  def test_stack_size_0
    assert_equal(0, @stack.size)
  end

  def test_push_pop_empty_again
    assert_raise(EmptyStackError) do
      @stack.push 1
      assert_equal(1, @stack.size)
      @stack.push 2
      assert_equal(2, @stack.size)
      @stack.push 3
      assert_equal(3, @stack.size)
      assert_equal(3, @stack.pop)
      assert_equal(2, @stack.size)
      assert_equal(2, @stack.pop)
      assert_equal(1, @stack.size)
      assert_equal(1, @stack.pop)
      assert_equal(0, @stack.size)
      @stack.pop
    end
  end
end