 Okay, hi everyone. So I've started to talk how to bring developing really cool languages. So introduction for languages testing. So it's me. So I'm from Tokyo, Japan. And I'm a member of Ruby Core team. And the main thing is Ruby Gems, and Reg, and Aldog, and the second, it says I have a, I maintained a lot of Ruby Gems. So how to contribute to OSS? Do you have an OSS product? So many people say OSS is great, so you can contribute to or develop OSS. Please do documentation. You imagine documentation is easy, okay? I will try to contribute the documentation to OSS. But documentation is hard, especially Ruby's situation. No one knows the true behavior of the Ruby languages. Only Mats knows it. On the other hand, testing and running code is easy. Ruby has a lot of test ecosystem, and the libraries, like MiTest, ASVEC, and CapValera, et cetera, et cetera. And now Bandware and Docker provides as an encapsulated environment. If you get test failures, you can submit issues to get to their tracker. If test coverage is missing for some Ruby code, you can also write new tests and submit a patch. Okay, you can contribute to Ruby languages now. These instructions are a minimum set of Ruby languages tests. Only six commands. It's easy to raise the application one. Not the need some middleware like MyCKL, PostGCKL, MyMameCashD, Redis, and et cetera. You can get the following that. I describe to these results. The entry point of MakeCommand is this file named CommonMK. This file contains these tasks. Only one of the main tasks is MakeTest command. This task to build by a BitTest Ruby, TestLessik, and TestNoneBug. BitTest Ruby means a boot-slap test. This test confirms the simple syntax of Ruby languages like this. Like this. This assertion conforms to class method returns class storing variable. This assertion proves to name method returns module name like M and A, CronCon, B. It's test. Next one is TestLessik. TestLessik has to assign variable assignment and method definition and more like this. It's a truly simple test. Who are required these tests? This answer is here. So if you're interested in developing to language virtual machine garbage collection and syntax and more, MakeTest helps you. Sometimes a member of Ruby Core will apply biggest internal changes. Their first goal is to test passive MakeTest command. Next one is MakeTestAll. MakeTestAll is near your side. If you are interested in our logger library, you can check logger with this instruction. MakeTestAll tests logger. It's given by test environment variables. And the TestAll supports parallel execution like this. TestEagle-J4. It's one of the test cases of TestAll. It is a array class test. It's simple to test using X unit style. You need to define test methods of the perfect test underscore. This test checks to migrate arrays instances. This test case of logger library. It is same as arrays one. So it's simple X unit style test, like a MeTest or a test unit. It is checked to our logger level of logger instance. And the test-exe-exe contains the CAPI tests. It's test of RV array-sized methods. It's a CAPI. If you are C extension gem answer, I recommend it to run these files. MakeCheck is another one. MakeCheck is a full task of the language testing. You need to invoke it before a submitting patch or a pre-request. MakeCheck. These tasks for you. So most of Ruby's can write a test code. You can write a language test using X unit style tests, same as your applications. And we have a side project named RubySpec. We only use it for regression checking. You can invoke RubySpec under the Ruby query repository. You need to run make update RubySpec and test RubySpec. If it uses MSpec, it's not RSpec, but MSpec provides a spec-style test case like this. Please check for details of this URL. If you are interested in compatibility of Ruby languages, C, Ruby, and J-Ruby, and Ruinies, and Opal, and the spec-style test, please do contribute to RubySpec. We welcome to submit a new test for Ruby 2.3 and 2.4. We release Ruby 2.4 per day one, Monday of this week. We will have some broken chances on Ruby 2.4, example for unification of integer and unicode case mappings and more. If you have a general library, please do test with Ruby 2.4, and please report to our trackers if you have a submitterview issue. And if you have some issue with Ruby languages, Ruby Core, please do to run the test and write a test and submit to our tracker. And we adopt to receive on the Github repository. So Ruby language test is easy. That's all, thank you.