Test cases for thread-safety in mocking libraries (http://redningja.com/dev/parallel-tests-with-single-database/)

.ruby-version

ruby-2.0.0-p353

README.md

These are simple examples of testing in parallel with different mocking/stubbing. Each file tests a different mocking library, but they all use Minitest as the test runner so we can take advantage of the parallel runner. Each file passes without being run in parallel. All except minitest fail when run in parallel.

Gemfile

source 'https://rubygems.org'

gem 'mocha', '1.1.0'
gem 'rspec-mocks', '3.0.0.beta2'
#gem 'rspec-mocks', '2.14.6'
gem 'minitest'

Gemfile.lock

GEM
  remote: https://rubygems.org/
  specs:
    metaclass (0.0.4)
    minitest (5.3.4)
    mocha (1.1.0)
      metaclass (~> 0.0.1)
    rspec-mocks (3.0.0.beta2)
      rspec-support (= 3.0.0.beta2)
    rspec-support (3.0.0.beta2)

PLATFORMS
  ruby

DEPENDENCIES
  minitest
  mocha (= 1.1.0)
  rspec-mocks (= 3.0.0.beta2)

minitest_mock.rb

# These pass.
require 'minitest/autorun'
require 'minitest/pride'

concurrency = 10
Minitest.parallel_executor = Minitest::Parallel::Executor.new(concurrency)
Minitest::Test.parallelize_me!

class SomeClass
  def some_method
  end
end

describe 'Minitest Object#stub' do

  concurrency.times do |idx|

    it "tests object stub #{idx}" do
      obj = SomeClass.new
      obj.stub :some_method, idx do
        sleep 1
        obj.some_method.must_equal idx
      end
    end

  end

end

describe Minitest::Mock do

  concurrency.times do |idx|

    it "tests Mock #{idx}" do
      obj = Minitest::Mock.new
      obj.expect :some_method, idx, [idx]
      sleep 1
      obj.some_method(idx).must_equal idx
      obj.verify
    end

  end

end

mocha.rb

# These fail.
require 'minitest/autorun'
require 'minitest/pride'
require 'mocha/setup'

concurrency = 10
Minitest.parallel_executor = Minitest::Parallel::Executor.new(concurrency)
Minitest::Test.parallelize_me!

class SomeClass
  def some_method
  end
end

describe 'Minitest Object#stub' do

  concurrency.times do |idx|

    it "tests object stub #{idx}" do
      obj = SomeClass.new
      obj.stubs(:some_method => idx)
      sleep 1
      obj.some_method.must_equal idx
    end

  end

end

describe Minitest::Mock do

  concurrency.times do |idx|

    it "tests Mock #{idx}" do
      obj = mock
      obj.expects(:some_method).returns(idx)
      sleep 1
      obj.some_method(idx).must_equal idx
    end

  end

end

rspec-mocks-2.14.6.rb

# These fail.
require 'minitest'
require 'minitest/spec'
Minitest.autorun
require 'minitest/pride'
require 'rspec/mocks'

concurrency = 10
Minitest.parallel_executor = Minitest::Parallel::Executor.new(concurrency)
Minitest::Test.parallelize_me!

class MiniTest::Spec
  before do |test_case|
    RSpec::Mocks.setup(test_case)
  end
  after do |test_case|
    begin
      RSpec::Mocks.verify
    ensure
      RSpec::Mocks.teardown
    end
  end
end

class SomeClass
end

describe 'stubbing' do

  concurrency.times do |idx|

    it "tests stubbing #{idx}" do
      obj = SomeClass.new
      obj.stub(:num).and_return(idx)
      sleep 1
      obj.num.must_equal idx
    end
  end

end

describe 'mocking' do

  concurrency.times do |idx|

    it "tests mocking #{idx}" do
      obj = double
      expect(obj).to receive(:num).and_return(idx)
      sleep 1
      obj.num.must_equal idx
    end
  end

end

rspec-mocks-3.0.0.beta2.rb

# These fail.
require 'minitest'
require 'minitest/spec'
Minitest.autorun
require 'minitest/pride'
require 'rspec/mocks'

RSpec::Mocks::Syntax.disable_expect
RSpec::Mocks::Syntax.enable_expect Minitest::Spec

concurrency = 10
Minitest.parallel_executor = Minitest::Parallel::Executor.new(concurrency)
Minitest::Test.parallelize_me!

class MiniTest::Spec
  include RSpec::Mocks::ExampleMethods

  before do |test_case|
    RSpec::Mocks.setup
  end
  after do |test_case|
    begin
      RSpec::Mocks.verify
    ensure
      RSpec::Mocks.teardown
    end
  end
end

class SomeClass
end

describe 'stubbing' do

  concurrency.times do |idx|

    it "tests object stub #{idx}" do
      obj = SomeClass.new
      allow(obj).to receive(:num).and_return(idx)
      sleep 1
      obj.num.must_equal idx
    end
  end

end

describe 'mocking' do

  concurrency.times do |idx|

    it "tests object stub #{idx}" do
      obj = double
      expect(obj).to receive(:num).and_return(idx)
      sleep 1
      obj.num.must_equal idx
    end
  end

end