如何使用 TDD 来解决答案未知的难题？

发布于 2024-10-09 07:46:43 字数 1970 浏览 8 评论 0原文

最近，我编写了一个 Ruby 程序来确定 “打乱方块” 方块拼图：

我使用 TDD 来实现大部分内容，导致测试看起来像这样：

it "has top, bottom, left, right" do
  c = Cards.new
  card = c.cards[0]
  card.top.should == :CT
  card.bottom.should == :WB
  card.left.should == :MT
  card.right.should == :BT
end

这对于较低级别的“辅助”方法效果很好：识别图块的“侧面”，确定图块是否可以有效地放置在网格中等等。

但是在编写实际算法来解决这个难题时，我遇到了一个问题。由于我不知道该问题的有效可能解决方案，我不知道如何首先编写测试。

我最终编写了一个非常丑陋的、未经测试的算法来解决它：

  def play_game
    working_states = []
    after_1 = step_1
    i = 0
    after_1.each do |state_1|
      step_2(state_1).each do |state_2|
        step_3(state_2).each do |state_3|
          step_4(state_3).each do |state_4|
            step_5(state_4).each do |state_5|
              step_6(state_5).each do |state_6|
                step_7(state_6).each do |state_7|
                  step_8(state_7).each do |state_8|
                    step_9(state_8).each do |state_9|
                      working_states << state_9[0]
                    end
                  end
                end
              end
            end
          end
        end
      end
    end

所以我的问题是：当您还不知道有效输出时，如何使用 TDD 编写方法？

如果您感兴趣，代码位于 GitHub：

原文

Recently I wrote a Ruby program to determine solutions to a "Scramble Squares" tile puzzle:

I used TDD to implement most of it, leading to tests that looked like this:

it "has top, bottom, left, right" do
  c = Cards.new
  card = c.cards[0]
  card.top.should == :CT
  card.bottom.should == :WB
  card.left.should == :MT
  card.right.should == :BT
end

This worked well for the lower-level "helper" methods: identifying the "sides" of a tile, determining if a tile can be validly placed in the grid, etc.

But I ran into a problem when coding the actual algorithm to solve the puzzle. Since I didn't know valid possible solutions to the problem, I didn't know how to write a test first.

I ended up writing a pretty ugly, untested, algorithm to solve it:

  def play_game
    working_states = []
    after_1 = step_1
    i = 0
    after_1.each do |state_1|
      step_2(state_1).each do |state_2|
        step_3(state_2).each do |state_3|
          step_4(state_3).each do |state_4|
            step_5(state_4).each do |state_5|
              step_6(state_5).each do |state_6|
                step_7(state_6).each do |state_7|
                  step_8(state_7).each do |state_8|
                    step_9(state_8).each do |state_9|
                      working_states << state_9[0]
                    end
                  end
                end
              end
            end
          end
        end
      end
    end

So my question is: how do you use TDD to write a method when you don't already know the valid outputs?

If you're interested, the code's on GitHub:

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