ruby-on-rails - 如何测试RuntimeError在Ruby中正确使用字符串插值？

Question

我有一个方法可以在数据库中记录对特定记录的更改，但是首先，它会在进一步检查之前检查类别类型的有效性。如果返回false，则会引发错误。

class UpgradePackageRecorder

  CATEGORIES = [ an array of categories here ... ]

  def initialize(category)
    @category = category
  end

  def record_change
    unless valid_category?
      raise "#{category} is not a recognized category"
    end

    other_methods
  end

  private

  def valid_category?
    CATEGORIES.include?(category)
  end

end

我开始为此编写rspec测试，以验证是否正确引发了错误。这是测试用例:

RSpec.describe UpgradePackageRecorder do
  describe '#record_change' do
    context 'the package type is invalid' do
      it 'raises an error' do

       recorder = UpgradePackageRecorder.new('Bronze')

       expect { recorder.record_change }.to raise_error(RuntimeError, /bronze is not a recognized category/)
      end
    end
  end
end

当我运行测试时，出现以下错误:

Failure/Error: raise "#{category} is not a recognized category"

RuntimeError:
  bronze is not a recognized category

为什么这样显示字符串插值？我也尝试过 category + ' is not a recognized category，但不能解决问题。

为了使这一点更加困惑，我取出了字符串插值，仍然看到了这个问题:

Failure/Error: raise "Unrecognized category"

RuntimeError:
  Unrecognized category

Answer 1

我想到了!

最终对我有用的语法是:

it 'raises an error' do

  expect do
    UpgradePackageRecorder.new(
      'Bronze'
    ).record_change
  end.to raise_error(
    RuntimeError, /bronze is not a recognized category/
  )

end

另外，在我删除的 expect块中还有另一个 it。它正在验证 record_change方法是否继续创建某个对象。