未定义的方法`use_transactional_tests =’表示#(NoMethodError)

undefined method `use_transactional_tests=' for #<RSpec::Core::Configuration:0x007fccf515e338> (NoMethodError)

在rails_helper.rb我经常使用这个,一切正常：

config.use_transactional_fixtures = true

但我收到了这个警告：

DEPRECATION WARNING: use_transactional_fixtures= is deprecated and will be removed from Rails 5.0 (use use_transactional_tests= instead). (called from block in <module:FixtureSupport> at /Users/monteirobrena/.rvm/gems/ruby-2.2.2@global/gems/rspec-rails-3.1.0/lib/rspec/rails/fixture_support.rb:25)

所以,我改变了我的rails_helper.rb以使用新的方式：

config.use_transactional_tests = true

现在我收到了这个错误：

/Users/monteirobrena/project/spec/rails_helper.rb:34:in `block in <top (required)>': undefined method `use_transactional_tests=' for #<RSpec::Core::Configuration:0x007fccf515e338> (NoMethodError)
from /Users/monteirobrena/.rvm/gems/ruby-2.2.2@global/gems/rspec-core-3.1.7/lib/rspec/core.rb:81:in `configure'
from /Users/monteirobrena/project/spec/rails_helper.rb:27:in `<top (required)>'
from /Users/monteirobrena/project/spec/controllers/messages_controller_spec.rb:1:in `require'
from /Users/monteirobrena/project/spec/controllers/messages_controller_spec.rb:1:in `<top (required)>'
from /Users/monteirobrena/.rvm/rubies/ruby-2.2.2/lib/ruby/gems/2.2.0/gems/rspec-core-3.1.7/lib/rspec/core/configuration.rb:1105:in `load'
from /Users/monteirobrena/.rvm/rubies/ruby-2.2.2/lib/ruby/gems/2.2.0/gems/rspec-core-3.1.7/lib/rspec/core/configuration.rb:1105:in `block in load_spec_files'
from /Users/monteirobrena/.rvm/rubies/ruby-2.2.2/lib/ruby/gems/2.2.0/gems/rspec-core-3.1.7/lib/rspec/core/configuration.rb:1105:in `each'
from /Users/monteirobrena/.rvm/rubies/ruby-2.2.2/lib/ruby/gems/2.2.0/gems/rspec-core-3.1.7/lib/rspec/core/configuration.rb:1105:in `load_spec_files'
from /Users/monteirobrena/.rvm/rubies/ruby-2.2.2/lib/ruby/gems/2.2.0/gems/rspec-core-3.1.7/lib/rspec/core/runner.rb:96:in `setup'
from /Users/monteirobrena/.rvm/rubies/ruby-2.2.2/lib/ruby/gems/2.2.0/gems/rspec-core-3.1.7/lib/rspec/core/runner.rb:84:in `run'
from /Users/monteirobrena/.rvm/rubies/ruby-2.2.2/lib/ruby/gems/2.2.0/gems/rspec-core-3.1.7/lib/rspec/core/runner.rb:69:in `run'
from /Users/monteirobrena/.rvm/rubies/ruby-2.2.2/lib/ruby/gems/2.2.0/gems/rspec-core-3.1.7/lib/rspec/core/runner.rb:37:in `invoke'
from /Users/monteirobrena/.rvm/gems/ruby-2.2.2@global/gems/rspec-core-3.1.7/exe/rspec:4:in `<top (required)>'
from /Users/monteirobrena/.rvm/rubies/ruby-2.2.2/bin/rspec:23:in `load'
from /Users/monteirobrena/.rvm/rubies/ruby-2.2.2/bin/rspec:23:in `<main>'
from /Users/monteirobrena/.rvm/gems/ruby-2.2.2@global/bin/ruby_executable_hooks:15:in `eval'
from /Users/monteirobrena/.rvm/gems/ruby-2.2.2@global/bin/ruby_executable_hooks:15:in `<main>'

有任何想法吗？谢谢.