用Ruby测试模块

我有一个模块，如下所示：

module FileTypeProcessor
  def self.read(input_path:, with_headers: nil, return_headers: nil)
    raise MethodNotImplementedError
  end

  def self.write(output_path:, data:)
    raise MethodNotImplementedError
  end
end

这就是我试图测试它的方式：

require 'spec_helper'

describe FileTypeProcessor do
  let(:dummy_class) { Class.new { extend FileTypeProcessor } }
  let(:input_path) { "some/input/path/file.csv" }
  let(:output_path) { "some/output/path/file.csv" }
  let(:data) { ['some', 'arbitrary', 'data'] }

  describe ".read" do
    subject { dummy_class.read(input_path: input_path) }

    it "raises an error if unimplemented" do
      expect{ subject }.to raise_error(MethodNotImplementedError)
    end
  end

但当我运行它时，我仍然得到了这个：

expected MethodNotImplementedError, got #<NoMethodError: undefined method `read' for #<Class:0x00007fd2820dc3f0>> with backtrace:

---

expected MethodNotImplementedError，get 35;您需要从模块中删除
self.

module FileTypeProcessor
  def read(input_path: nil, with_headers: nil, return_headers: nil)
    raise MethodNotImplementedError
  end
end

Class.new { extend FileTypeProcessor }.read # => MethodNotImplemented

如果希望能够通过模块调用这些方法，则必须将它们标记为公共模块函数：

module FileTypeProcessor
  def read(input_path: nil, with_headers: nil, return_headers: nil)
    raise MethodNotImplementedError
  end
  module_function :read
  public :read
end

FileTypeProcessor.read # => MethodNotImplemented
Class.new { extend FileTypeProcessor }.read # => MethodNotImplemented
Class.new { include FileTypeProcessor }.new.read # => MethodNotImplemented