问题

class Person
  attr_reader :name # 但没有 attr_accessor
  def initialize(name)
    @name = name
  end
end

FactoryBot.define do
  factory :person do
    name { 'Grace' }
  end
end

如何使用 factory_bot 创建一个 Person？如果尝试 build :person，会出现以下错误：

NoMethodError .. undefined method `name='

我编写了一个自定义构建策略，它可以工作，但我对它不满意，因为我不得不使用 instance_variable_get 来访问私有库对象。

class BuildNew
  def association(runner)
    runner.run
  end

  # @param evaluation [FactoryBot::Evaluation]
  def result(evaluation)
    attributes = evaluation.hash
    model_class = evaluation.instance_variable_get(:@attribute_assigner).send(:build_class_instance).class
    model_class.new(attributes)
  end
end
FactoryBot.register_strategy(:build_new, BuildNew)

<details>
<summary>英文:</summary>

Given a data model that lacks accessor methods,

```ruby
class Person
  attr_reader :name # but NO attr_accessor
  def initialize(name)
    @name = name
  end
end

FactoryBot.define do
  factory :person do
    name { &#39;Grace&#39; }
  end
end

How can I use factory_bot to build a Person? If we try build :person we get:

NoMethodError .. undefined method `name='

I wrote a custom build strategy which works, but I am not pleased with it because I had to use instance_variable_get to access private library objects.

class BuildNew
  def association(runner)
    runner.run
  end

  # @param evaluation [FactoryBot::Evaluation]
  def result(evaluation)
    attributes = evaluation.hash
    model_class = evaluation.instance_variable_get(:@attribute_assigner).send(:build_class_instance).class
    model_class.new(attributes)
  end
end
FactoryBot.register_strategy(:build_new, BuildNew)

答案1

得分: 2

以下是翻译好的部分：

似乎自定义构建策略是不必要的。可以使用 initialize_with 更简单地完成这个任务。

FactoryBot.define do
  factory :person do
    initialize_with { new(attributes) }
    name { 'Grace' }
  end
end

FactoryBot.define do
  factory :person do
    initialize_with { new(attributes) }
    name { 'Grace' }
  end
end