ruby-on-rails - 比较 float 组时 rspec 测试的舍入问题

Question

有一个方法我想检查结果:

 result.should  == [1.0,2.0,3.0]

但是我得到一个错误:

   expected: [1.0, 2.0, 3.0]
        got: [1.0, 2.0, 3.0] (using ==)

我认为是四舍五入的问题，但我不知道如何比较它们，例如偏差为 0.1。

谢谢你，apneadiving。我写了自己的匹配器，如果它对某人有帮助的话:

RSpec::Matchers.define :be_closed_array do |expected, truth|
  match do |actual|
    same = 0
    for i in 0..actual.length-1
      same +=1 if actual[i].round(truth) == expected[i].round(truth)
    end
    same == actual.length
  end

  failure_message_for_should do |actual|
    "expected that #{actual} would be close to #{expected}"
  end

  failure_message_for_should_not do |actual|
    "expected that #{actual} would not be close to #{expected}"
  end

  description do
    "be a close to #{expected}"
  end
end

Answer 1

使用(自 2.7.0 后弃用，在 3.0.0 中删除):

 .should be_close

甚至:

 .should be_within

引用此处 http://rubydoc.info/gems/rspec-expectations/2.4.0/RSpec/Matchers