Rails 6升级至Rails 7后测试报错：each_value方法未定义

问题描述 #

将Rails 6项目升级至Rails 7以集成Tailwind后，项目运行正常，但执行任何测试都会报错。移除所有测试可正常通过，添加最简测试代码后执行rails t仍触发错误。

最简测试代码（post_test.rb） #

require "test_helper"

class PostTest < ActiveSupport::TestCase
  test "the truth" do
    assert true
  end
end

报错详情 #

rails t
Running 1 tests in a single process (parallelization threshold is 50)
Run options: --seed 58982

# Running:

E

Error:
PostTest#test_the_truth:
NoMethodError: undefined method `each_value' for nil:NilClass

        @stubs.each_value do |object_stubs|
              ^^^^^^^^^^^
    /home/sam/.rvm/gems/ruby-3.1.0/gems/activesupport-7.0.3.1/lib/active_support/testing/time_helpers.rb:39:in `unstub_all!'
    /home/sam/.rvm/gems/ruby-3.1.0/gems/activesupport-7.0.3.1/lib/active_support/testing/time_helpers.rb:211:in `travel_back'
    /home/sam/.rvm/gems/ruby-3.1.0/gems/activesupport-7.0.3.1/lib/active_support/testing/time_helpers.rb:71:in `after_teardown'
    /home/sam/.rvm/gems/ruby-3.1.0/gems/activesupport-7.0.3.1/lib/active_support/current_attributes/test_helper.rb:10:in `after_teardown'
    /home/sam/.rvm/gems/ruby-3.1.0/gems/activesupport-7.0.3.1/lib/active_support/execution_context/test_helper.rb:10:in `after_teardown'
    /home/sam/.rvm/gems/ruby-3.1.0/gems/activerecord-7.0.3.1/lib/active_record/test_fixtures.rb:15:in `after_teardown'
    /home/sam/.rvm/gems/ruby-3.1.0/gems/activesupport-7.0.3.1/lib/active_support/testing/setup_and_teardown.rb:51:in `after_teardown'


rails test test/models/post_test.rb:7


Finished in 0.036355s, 27.5065 runs/s, 27.5065 assertions/s.
1 runs, 1 assertions, 0 failures, 1 errors, 0 skips    

补充配置文件 #

test_helper.rb #

require_relative "../config/environment"
require "rails/test_help"

class ActiveSupport::TestCase
  # Run tests in parallel with specified workers
  parallelize(workers: :number_of_processors)

  # Setup all fixtures in test/fixtures/*.yml for all tests in alphabetical order.
  fixtures :all

  # Add more helper methods to be used by all tests here...
end

config/environments/test.rb #

require "active_support/core_ext/integer/time"

# The test environment is used exclusively to run your application's
# test suite. You never need to work with it otherwise. Remember that
# your test database is "scratch space" for the test suite and is wiped
# and recreated between test runs. Don't rely on the data there!

Rails.application.configure do
  # Settings specified here will take precedence over those in config/application.rb.

  # Turn false under Spring and add config.action_view.cache_template_loading = true.
  config.cache_classes = true

  # Eager loading loads your whole application. When running a single test locally,
  # this probably isn't necessary. It's a good idea to do in a continuous integration
  # system, or in some way before deploying your code.
  config.eager_load = ENV["CI"].present?

  # Configure public file server for tests with Cache-Control for performance.
  config.public_file_server.enabled = true
  config.public_file_server.headers = {
    "Cache-Control" => "public, max-age=#{1.hour.to_i}"
  }

  # Show full error reports and disable caching.
  config.consider_all_requests_local       = true
  config.action_controller.perform_caching = false
  config.cache_store = :null_store

  # Raise exceptions instead of rendering exception templates.
  config.action_dispatch.show_exceptions = false

  # Disable request forgery protection in test environment.
  config.action_controller.allow_forgery_protection = false

  # Store uploaded files on the local file system in a temporary directory.
  config.active_storage.service = :test

  config.action_mailer.perform_caching = false

  # Tell Action Mailer not to deliver emails to the real world.
  # The :test delivery method accumulates sent emails in the
  # ActionMailer::Base.deliveries array.
  config.action_mailer.delivery_method = :test

  # Print deprecation notices to the stderr.
  config.active_support.deprecation = :stderr

  # Raise exceptions for disallowed deprecations.
  config.active_support.disallowed_deprecation = :raise

  # Tell Active Support which deprecation messages to disallow.
  config.active_support.disallowed_deprecation_warnings = []

  # Raises error for missing translations.
  # config.i18n.raise_on_missing_translations = true

  # Annotate rendered view with file names.
  # config.action_view.annotate_rendered_view_with_filenames = true
end

解决办法 #

1. 禁用并行测试 #

在test_helper.rb中注释掉并行测试配置：

# parallelize(workers: :number_of_processors)

并行测试可能导致测试间状态污染，尤其是时间相关的stub未被正确清理。

2. 手动初始化TimeHelpers的stubs #

在ActiveSupport::TestCase中添加setup钩子初始化变量：

class ActiveSupport::TestCase
  # ... 现有代码 ...

  setup do
    @stubs ||= {}
  end
end

确保@stubs在测试执行前被初始化，避免调用each_value时对象为nil。

3. 升级Rails版本 #

该bug已在Rails 7.0.4及后续版本中修复。执行以下命令升级到最新7.0.x版本：

bundle update rails

内容的提问来源于stack exchange，提问作者user7203397