RSpec MustBeConfiguredBeforeExampleGroupsError on plain project - ruby-on-rails

Question

I'm setting up a Rails 3.1 project and like to properly test it using RSpec.
After running rails g rspec:install and further running rspec, the console messages read as follows:
% rspec
/Library/Ruby/Gems/1.8/gems/rspec-core-2.7.0/lib/rspec/core/configuration.rb:470:in `assert_no_example_groups_defined': RSpec's mock_framework configuration option must be configured before any example groups are defined, but you have already defined a group. (RSpec::Core::Configuration::MustBeConfiguredBeforeExampleGroupsError)
from /Library/Ruby/Gems/1.8/gems/rspec-core-2.7.0/lib/rspec/core/configuration.rb:168:in `mock_framework='
from /Library/Ruby/Gems/1.8/gems/rspec-core-2.7.0/lib/rspec/core/configuration.rb:142:in `mock_with'
from /Users/ened/project/spec/controllers/../spec_helper.rb:19
from /Library/Ruby/Gems/1.8/gems/rspec-core-2.7.0/lib/rspec/core.rb:71:in `configure'
from /Users/ened/project/spec/controllers/../spec_helper.rb:11
from /Library/Ruby/Gems/1.8/gems/activesupport-3.1.0/lib/active_support/dependencies.rb:240:in `require'
from /Library/Ruby/Gems/1.8/gems/activesupport-3.1.0/lib/active_support/dependencies.rb:240:in `require'
from /Library/Ruby/Gems/1.8/gems/activesupport-3.1.0/lib/active_support/dependencies.rb:225:in `load_dependency'
from /Library/Ruby/Gems/1.8/gems/activesupport-3.1.0/lib/active_support/dependencies.rb:240:in `require'
from /Users/ened/project/spec/controllers/submissions_controller_spec.rb:1
from /Library/Ruby/Gems/1.8/gems/activesupport-3.1.0/lib/active_support/dependencies.rb:234:in `load'
from /Library/Ruby/Gems/1.8/gems/activesupport-3.1.0/lib/active_support/dependencies.rb:234:in `load'
from /Library/Ruby/Gems/1.8/gems/activesupport-3.1.0/lib/active_support/dependencies.rb:225:in `load_dependency'
from /Library/Ruby/Gems/1.8/gems/activesupport-3.1.0/lib/active_support/dependencies.rb:234:in `load'
from /Library/Ruby/Gems/1.8/gems/rspec-core-2.7.0/lib/rspec/core/configuration.rb:459:in `load_spec_files'
from /Library/Ruby/Gems/1.8/gems/rspec-core-2.7.0/lib/rspec/core/configuration.rb:459:in `map'
from /Library/Ruby/Gems/1.8/gems/rspec-core-2.7.0/lib/rspec/core/configuration.rb:459:in `load_spec_files'
from /Library/Ruby/Gems/1.8/gems/rspec-core-2.7.0/lib/rspec/core/command_line.rb:18:in `run'
from /Library/Ruby/Gems/1.8/gems/rspec-core-2.7.0/lib/rspec/core/runner.rb:80:in `run_in_process'
from /Library/Ruby/Gems/1.8/gems/rspec-core-2.7.0/lib/rspec/core/runner.rb:69:in `run'
from /Library/Ruby/Gems/1.8/gems/rspec-core-2.7.0/lib/rspec/core/runner.rb:10:in `autorun'
from /usr/bin/rspec:19
My rspec/spec_helper.rb looks like this:
# This file is copied to spec/ when you run 'rails generate rspec:install'
ENV["RAILS_ENV"] ||= 'test'
require File.expand_path("../../config/environment", __FILE__)
require 'rspec/rails'
require 'rspec/autorun'
# Requires supporting ruby files with custom matchers and macros, etc,
# in spec/support/ and its subdirectories.
Dir[Rails.root.join("spec/support/**/*.rb")].each {|f| require f}
RSpec.configure do |config|
# == Mock Framework
#
# If you prefer to use mocha, flexmock or RR, uncomment the appropriate line:
#
# config.mock_with :mocha
# config.mock_with :flexmock
# config.mock_with :rr
config.mock_with :rspec
# Remove this line if you're not using ActiveRecord or ActiveRecord fixtures
config.fixture_path = "#{::Rails.root}/spec/fixtures"
# If you're not using ActiveRecord, or you'd prefer not to run each of your
# examples within a transaction, remove the following line or assign false
# instead of true.
config.use_transactional_fixtures = true
# If true, the base class of anonymous controllers will be inferred
# automatically. This will be the default behavior in future versions of
# rspec-rails.
config.infer_base_class_for_anonymous_controllers = false
end
I thought it's configured already using the config.mock_with ? I'm puzzled, what is missing?

Answer 1

I just hit this. It turned out to be that some of my old (circa RSpec 1) specs had the following require statement:
require File.expand_path(File.dirname(__FILE__) + '/../spec_helper')
Most of the new specs had this require statement:
require 'spec_helper'
I'd never bothered to tidy up the old style. What this meant was that the spec_helper.rb filename was passed to require in two different ways: one full path, one local path. This in turn caused spec_helper.rb to be executed twice, triggering the error. Changing all the require statements to the short new style fixed the issue.

Answer 2

I just resolved this problem for my Rails app.
My problem was that two spec files were missing the require 'spec_helper' line at the top of the file.

Answer 3

I met the same problem, and my root cause is:
there are some spec files exist in spec/support folder!
e.g.
spec/support/xx_spec.rb
which looks like:
require 'spec_helper'
describe XX do
...
and in the spec/spec_helper.rb file, there are:
Dir[Rails.root.join("spec/support/**/*.rb")].each {|f| require f}
This is a situation that 'spec_helper' was recursive required for unlimited times.
So the solution is very simple:
REMOVE all the xx_spec.rb files from spec/support folder.

Answer 4

Could be an issue of Dir[Rails.root.join("spec/support/**/*.rb")].each {|f| require f}. I have placed it below the config block in my app and it worked.