使用 Minitest，如何对几个不同的类方法进行存根调用

Question

使用 Minitest 时如何对几个不同的类方法进行存根或模拟调用？

比如我想测试一下这个方法：

  def index
    categories = CategoryAnalyzer.for_user(current_user)
    @root_categories = categories.select { |c| c.parent_id.nil? }
    @max_depth = CategoryAnalyzer.max_depth(categories)
    @children_by_id = CategoryAnalyzer.children_by_id(categories)
  end 

请注意，它在

CategoryAnalyzer

上调用三个单独的类方法。有没有一种方法可以存根或模拟所有三种方法（

for_user

、

max_depth

和

children_by_id

），并且不需要将对

stub

的一个调用嵌套在对

stub

的另一个调用的块中？

Answer 1

您可以使用

Minitest::Mock

类创建模拟对象并在其上存根不同的方法。

例如-

require 'minitest/autorun'

class UserProfileTest < Minitest::Test
  def test_index_method
    # Create a mock object
    category_analyzer_mock = Minitest::Mock.new
    # Stub the for_user method, for user categories
    category_analyzer_mock.expect(:for_user, mocked_categories, [mocked_user])
    # Stub the max_depth method
    category_analyzer_mock.expect(:max_depth, mocked_max_depth, [mocked_categories])

    # Replace the original MyCategories with the mock
    MyCategories.stub(:new, category_analyzer_mock) do
      #test code that calls index method
      #you can call the method on an instance of your controller
      controller = UserProfile.new
      controller.index

      # Assertions based on the expected behavior of your method
      assert_equal expected_root_categories, controller.instance_variable_get(:@root_categories)
      assert_equal expected_max_depth, controller.instance_variable_get(:@max_depth)
    end

    # Verify that the expected methods were called
    category_analyzer_mock.verify
  end

  private

  def mocked_user
    #return a mocked user
  end

  def mocked_categories
    #return mocked categories
  end

  def mocked_max_depth
    #return mocked value
  end
end