ruby-on-rails - 测试和建立连接

Question

如何为establish_connection模型中使用的项目编写测试以连接到另一个数据库？

Answer 1

当您为某些模型执行建立连接以连接到不同的数据库时，您在测试这些表时将面临的问题之一是您创建的测试数据不会自动回滚。

创建事务保存点和回滚测试数据的实际代码位于rails/activerecord/lib/active_record/fixtures.rb. 特别是有两种方法setup_fixtures和teardown_fixtures。这些方法中的代码是直截了当的。他们只是创建一个保存点并为每个测试进行回滚。但它只用于ActiveRecord::Base连接。

所以你要做的就是“猴子补丁”这些方法，这样，除了ActiveRecord::Base连接之外，你的附加数据库连接也完成了相同的一组操作。

这是相同的示例代码：

## database.yml
development:
  database: dev
test:
  database: test
#...
my_connection_development:
  database: my_connection_dev
my_connection_test:
  database: my_connection_test
#...

## my_connection_base.rb
class MyConnectionBase < ActiveRecord::Base
  establish_connection(ActiveRecord::Base.configurations["my_connection_#{RAILS_ENV}"])
  self.abstract_class = true
end

## my_model.rb
class MyModel < MyConnectionBase
end

## my_another_model.rb
class MyAnotherModel < MyConnectionBase
end

## test_case_patch.rb
module ActiveSupport
  class TestCase
    def setup_fixtures
      return unless defined?(ActiveRecord) && !ActiveRecord::Base.configurations.blank?
      if pre_loaded_fixtures && !use_transactional_fixtures
        raise RuntimeError, 'pre_loaded_fixtures requires use_transactional_fixtures'
      end
      @fixture_cache = {}
      @@already_loaded_fixtures ||= {}
      # Load fixtures once and begin transaction.
      if run_in_transaction?
        if @@already_loaded_fixtures[self.class]
          @loaded_fixtures = @@already_loaded_fixtures[self.class]
        else
          load_fixtures
          @@already_loaded_fixtures[self.class] = @loaded_fixtures
        end

        ActiveRecord::Base.connection.increment_open_transactions
        ActiveRecord::Base.connection.transaction_joinable = false
        ActiveRecord::Base.connection.begin_db_transaction

        MyConnectionBase.connection.increment_open_transactions
        MyConnectionBase.connection.transaction_joinable = false
        MyConnectionBase.connection.begin_db_transaction
      # Load fixtures for every test.
      else
        Fixtures.reset_cache
        @@already_loaded_fixtures[self.class] = nil
        load_fixtures
      end
      # Instantiate fixtures for every test if requested.
      instantiate_fixtures if use_instantiated_fixtures
    end

    def teardown_fixtures
      return unless defined?(ActiveRecord) && !ActiveRecord::Base.configurations.blank?
      unless run_in_transaction?
        Fixtures.reset_cache
      end
      # Rollback changes if a transaction is active.
      if run_in_transaction? && MyConnectionBase.connection.open_transactions != 0
        MyConnectionBase.connection.rollback_db_transaction
        MyConnectionBase.connection.decrement_open_transactions
      end
      # Rollback changes if a transaction is active.
      if run_in_transaction? && ActiveRecord::Base.connection.open_transactions != 0
        ActiveRecord::Base.connection.rollback_db_transaction
        ActiveRecord::Base.connection.decrement_open_transactions
      end
      MyConnectionBase.clear_active_connections!
      ActiveRecord::Base.clear_active_connections!
    end
  end
end

Answer 2

在您将建立连接放入模型后，我认为不需要更改测试代码，因为您仍然测试相同的模型功能。

Answer 3

您不需要测试建立连接方法，因为它是一个 activrecord 方法，并且在发布之前经过了很好的测试。

尽管如果您仍然想这样做，请在不同的方法中调用该方法，并查看您是否可以连接到该数据库中的适当表。