Question

我不确定如何在以下的intersection.rb

中测试#create_arr

intersection.rb

class Intersection

  def initialize(xa1, ya1, xa2, ya2, xb1, yb1, xb2, yb2 )
    @xa1 = xa1.to_i
    @ya1 = ya1.to_i
    @xa2 = xa2.to_i
    @ya2 = ya2.to_i
    @xb1 = xb1.to_i
    @yb1 = yb1.to_i
    @xb2 = xb2.to_i
    @yb2 = yb2.to_i

  end
  # compare sizes 
  # both can't have the same size
  def self.check_size?
    rec1 = [(@xa2-@xa1).abs, (@ya2-@ya1).abs]
    rec2 = [(@xb2-@xb1).abs, (@yb2-@yb1).abs]
    rec1 == rec2 or rec1 == rec2.reverse
    # rec1<<rec2.reverse
  end

  def self.create_arr(a, b, c, d)
    (a..c).to_a.product((b..d).to_a)
  end


...
end

intersection_spec.rb

require './spec_helper'
require './intersection.rb'

describe Intersection do
  before do
    # YES
    @xa1 = 0.0
    @ya1 = 0.0
    @xa2 = 5.0
    @ya2 = 5.0
    @xb1 = 1.0 
    @yb1 = 1.0
    @xb2 = 4.0
    @yb2 = 4.0
    @intersection = Intersection.new(@xa1, @ya1, @xa2, @ya2, @xb1, @yb1, @xb2, @yb2)
  end

  specify{ expect(@intersection.create_arr(@xa1, @ya1, @xa2, @ya2)).to eq [[0,0], [0,1], [0,2], [0,3], [0,4], [0,5], [1,0], [1,1], [1,2], [1,3], [1,4], [1,5], [2,0], [2,1], [2,2], [2,3], [2,4], [2,5], [3,0], [3,1], [3,2], [3,3], [3,4], [3,5], [4,0], [4,1], [4,2], [4,3], [4,4], [4,5], [5,0], [5,1], [5,2], [5,3], [5,4], [5,5]] }

end

这会给TypeError: can't iterate from Float。

我能做的一种方法是改变@xa1 = (1.0).to_i但是我在初始化中所做的事情变得毫无用处。

测试带参数的#create_arr的最佳方法是什么？

Answer 1

您将遇到的一个问题是您的create_arr方法是Intersection上的类方法。您遇到的问题可能与在类的实例上调用类方法有关。

我建议简要回顾一下Class＆amp; amp;实例方法，以了解那里发生了什么。 RailsTips对差异进行了很好的探索。

要使用下面的create_arr方法，您可以调用Intersection.create_arr（...）而不是@ intersection.create_arr（...）。

class Intersection
...
  def self.create_arr(a, b, c, d)
    (a..c).to_a.product((b..d).to_a)
  end    
...
end

要将方法更改为实例方法，请删除自我。＆＃39;来自类中的方法声明。这样你就可以通过@ intersection.create_arr（...）在Intersection类的实例上调用create_arr。

class Intersection
...
  def create_arr(a, b, c, d)
    (a..c).to_a.product((b..d).to_a)
  end    
...
end

最后，要解决有关测试课程的其他问题。我建议使用＆＃39;它＆＃39;块和＆＃39;。应该＆＃39;澄清你的RSpec。我在下面列出了代码的示例重构。

class Intersection
...
  #=> refactored to use arrays and ranges for 4 arguments, you could make this take range values as params to make this less tied to arrays of 4 objects.
  def self.create_arr(args = [])
    args[0..2].product(args[1..3])
  end    
...
end

require './spec_helper'
require './intersection.rb'

describe Intersection do
  before do
    @xa1 = 0.0
    @ya1 = 0.0
    @xa2 = 5.0
    @ya2 = 5.0
    @xb1 = 1.0 
    @yb1 = 1.0
    @xb2 = 4.0
    @yb2 = 4.0
    @intersection = Intersection.new(@xa1, @ya1, @xa2, @ya2, @xb1, @yb1, @xb2, @yb2)
  end

  it 'creates an array of tuples' do
    @expected_results = [[0,0], [0,1], [0,2], [0,3], [0,4], [0,5], [1,0], [1,1], [1,2], [1,3], [1,4], [1,5], [2,0], [2,1], [2,2], [2,3], [2,4], [2,5], [3,0], [3,1], [3,2], [3,3], [3,4], [3,5], [4,0], [4,1], [4,2], [4,3], [4,4], [4,5], [5,0], [5,1], [5,2], [5,3], [5,4], [5,5]]
    @results = Intersection.create_arr([@xa1, @ya1, @xa2, @ya2])
    @results.should eq(@expected_results)
  end
end

如何在Ruby中使用参数测试方法

1 个答案: