Ruby
A Big Look at MiniTest
Summarized using AI
A Big Look at MiniTest
by Mark BatesIn his talk at RubyConf AU 2014, Mark Bates provides an overview of MiniTest, a lightweight testing framework included with Ruby starting from version 1.9. He discusses its benefits, structure, and how it can effectively be used in both simple and Rails applications. The core themes of the presentation include:
Introduction to MiniTest: Mark highlights that MiniTest is often overlooked despite its powerful capabilities, which are bundled with Ruby.
Comparison to Other Testing Frameworks: He contrasts MiniTest with RSpec and TestUnit, pointing out that while RSpec provides extensive functionality, most of what developers need can be achieved using MiniTest with less complexity.
Key Features of MiniTest: The framework is composed of eight files, three of which are essential. Mark emphasizes its simple syntax and structure similar to RSpec, making it easily accessible for developers already familiar with Ruby testing.
Custom Matchers and Assertions: Mark illustrates how developers can write custom matchers in MiniTest, allowing them to tailor the testing framework to their specific needs without cluttering the object space.
Mocking and Stubbing: He mentions that mocking and stubbing can significantly enhance test performance. Mark encourages using Ruby's built-in capabilities along with existing libraries like Mocha or FlexMock for complex scenarios.
Best Practices in MiniTest: Mark emphasizes the importance of maintaining clean tests through the use of expectations that start with 'must_' which prevents pollution of the kernel object space.
Integration with Rails: He discusses how MiniTest can be set up effortlessly within a Rails application and encourages the audience to consider its use over more complex alternatives, especially in speed and efficiency.
CI Tool Compatibility: MiniTest works seamlessly with Continuous Integration (CI) tools like Travis CI, enhancing its usability in modern development environments.
Mark concludes by encouraging Ruby developers to utilize MiniTest, highlighting its ease of installation, speed, and the substantial amount of functionality it offers, noting available resources for further learning at RubyConf AU 2014. By promoting practical use cases and strategies within the framework, he aims for developers to adopt MiniTest for efficient and effective testing in their projects.
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Thank you! There's popcorn downstairs, and Andres is downstairs now. Here we've got this to mark.
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J-Mac is a big person with a big smile who loves big hugs. True? Bring it here!
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Okay, bringing the big booming bear hug.
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The hug is authored by a programming book in CoffeeScript. He's Paul McCartney's cousin.
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Don't ask him to sing. Please welcome my fate—and so did that!
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I want to just give you an introduction. I am NOT Paul McCarthy's cousin, but ask me later, and I do have a really, really good Paul McCartney story for you.
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I am also not Ryan Bates, if that is what you were expecting to see. Hi Josh, thanks for coming!
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I am the author of three books: "Programming in CoffeeScript," "Distributed Programming with Ruby," and my latest, "Conquering the Command Line." I have some to give away!
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This is what it looks like when you win one! I'm very excited—this is not me trying to bash my head on this thing, by the way.
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So, if I suddenly fall unconscious, don’t be alarmed. I do have a couple of giveaways.
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Before I do that though, I'm also the voice behind a site called Metacast.TV. It features weekly screencasts about Ruby, Rails, JavaScript, Postgres, and Go.
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It's a lot of fun! Enjoy a free month of Ruby AU 2014, and learn about all sorts of things. So before I give away books and before we dive into MiniTest, I know who really went to the GitHub drink-up last night!
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Good number of people. Who here flew in from really far away very recently? And who here is just generally tired this morning?
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That's what I thought, so let's all stand up! If you said you weren’t tired, we wouldn't do this. Let's all stand up!
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There we go, let’s get the blood flowing. Everybody stand up, come on. Roko t-shirt, stand up! It's a small room!
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Now, everybody reach up into the sky! Good! Now reach out for every t-shirt!
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Alright, let’s all do some twists. Everybody do some twists! Stretch it out!
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Waking up, that’s good! We like to get people moving.
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Now everybody, let's stay standing for just a minute.
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Today we're going to take a big look at MiniTest. Alright?
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This is the Green Dot—it’s what Rubyists love! I’ll be honest, my wife is here with me in Sydney.
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If she wasn't, I'd probably be making out with the Green Dot in my hotel room at night! That's how much I love the Green Dot.
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Nothing makes us feel better than to see a bunch of green dots going across our screen.
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Red dots make us sad, green dots make us happy! When we see a screen like this, we all know we can sleep well at night.
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We know our code is perfect, wonderful, and very well tested. Okay, maybe not perfect, especially if you're writing Zach's code.
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But, it's at least somewhat tested, right? Green dots make us happy.
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Alright, let's get back to serious business.
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The first thing we do when we set up a new project is set up a testing framework.
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At this point, you usually think, 'Oh my god! I should write my own testing framework, because how hard could it be?' Who here has thought that before?
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Raise your hand! At least one person has.
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I'm here to say, please don’t! And I’ll tell you why.
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There’s a site called the Ruby Toolbox; who here has heard of the Ruby Toolbox?
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Fantastic! It's an amazing site written by a big hulking German guy named Christoph.
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If you see Christophe, buy him a drink. He smokes a lot, drinks a lot, so he’ll be open to that!
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But the Ruby Toolbox is a great place. You can go find a new plugin for your app.
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I want to write that tags for my application, what's the latest and greatest?
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It gives you a lot of information. Here is the MiniTest one, for example.
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It tells you the last time it was updated, how many commits, and how many downloads.
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It's a really helpful tool to get a good idea of what these plugins are and what they do.
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I did a little search for testing unit testing plugins, and these are some of the ones I found.
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I know RSpec, MiniTest, TestUnit, Bacon, and it starts getting a little wonky as we go along here.
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Other people have had your idea, and I'm here to tell you, don't do it!
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The reason is we already have MiniTest. MiniTest is already with us, and it's there every day. Most people don’t realize we have it.
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Good things indeed come in small packages, as we can all agree. The Mini Cooper—everybody loves the Mini Cooper!
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Mini me, who doesn’t love Mini Me?
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You get mini bottles of booze on airplanes that make you feel like a giant!
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And when you hold them, it’s a fun feeling!
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Anyway, back to the topic of MiniTest: MiniTest comes in eight files.
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Honestly, there are about three that actually do anything. For example, one is a gay pride formatter that will rainbow color your test results.
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It’s awesome, although probably not incredibly useful.
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It really comes down to about three different files that make up a solid testing framework.
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This is a little bit of what MiniTests look like. This was the MiniTest spec; it looks very much like RSpec, as we will see going forward.
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This is MiniTest unit, for those of you who have a preference for test unit.
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Now, one interesting thing to note about these two files I just showed you is if you were to take the time and quickly type these into Vim or Sublime.
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Then run them as Ruby; chances are they would run for you and the tests would actually pass.
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And we did that without any gems! How the heck do we do that?
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It ships with Ruby people! It's there, on your computer, already!
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If you have Ruby greater than 1.9, and why don't you if you don’t? Seriously!
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If you have Ruby 1.9 or above, you already have MiniTest.
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You have what you need to run testing. It is also available as a gem.
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The reason why it's available is that the gem is easier to develop outside of the Ruby pipeline.
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So I highly recommend you use the gem. You can install it with 'gem install mini-test'.
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But if you're on a long flight from LA to Sydney with no internet, you can still write tests without needing Bundler.
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It has a very familiar syntax to RSpec.
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Who here has used RSpec before? Who here has never used RSpec?
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Now, I know you're timid... who here uses TestUnit?
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Really? Oh, you poor thing! We'll buy you a drink later to help you out!
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So, Ruby 1.9 refers to MiniTest to replace the TestUnit in the Ruby core library.
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Thus it is readily available to you.
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We'll take a quick look at the basics, and some of the differences between MiniTest, Spec, and Test Unit.
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Who here is involved with Rails and are you excited?
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It’s coming up. I think it has a bright future.
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So, here's a basic MiniTest spec: describe something, do it, it does something.
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These are all very RSpec-like. If you already know RSpec, you know what you need to be familiar with MiniTest.
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I could probably end the talk right there and still cover before and after setups and teardowns.
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We can do nesting, just like we'd expect!
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For those who don't know what lets are, lets memorize or encapsulate what's inside that code block.
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That allows us to access another place, just like RSpec.
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We also have subjects, just like RSpec.
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What’s fascinating about this is that I keep saying 'just like RSpec', but if you go into a project that uses RSpec and do 'bundle open RSpec'...
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You can see how many files are there.
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Then do 'bundle open' on all the files for all the gems that RSpec requires.
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Then go and look at the MiniTest code to see how much they can do in three files.
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Versus what RSpec does in about six gems.
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It’s important to see, you can achieve similar results.
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Context blocks, we can’t do context blocks in MiniTests.
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If you run that, you get an undefined method context.
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But we can fix that easily by aliasing it off.
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It's quite simple to alias context to describe—it’s just pure Ruby!
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We can do pendings with MiniTests.
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There are three different ways to do that: it does something without a block.
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We can skip it, or we can skip with a message.
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Pretty straightforward! Run that, and you'll have a bunch of successful tests.
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Expectations, this is one of the things I like most about MiniTests.
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It's got really nice expectations that are very simple.
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They don’t clutter up your object space like other testing frameworks such as RSpec.
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These are the expectations that are included with MiniTests.
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They all start with 'must_'.
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So when you're looking at the methods that are available, you know which ones belong to MiniTests.
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They all run with 'must_' which keeps things neat.
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You won't pollute the kernel object space or your object’s space.
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It’s very clean and simple, like 'must be empty', 'must respond to', 'must send', 'must have output', etc.
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Also, the opposite is 'won't'.
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If you know one, you'll remember the other. For instance, 'must be' means it won't be.
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Or 'must match' meaning it won’t match. Very straightforward!
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Here's a little code showing you what a bunch of them achieve.
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You have 'must raise', 'must include', 'won't include', 'must be nil', 'must be empty', and many more.
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I love the assertiveness of this framework. It’s not wishy-washy; it clearly states expectations.
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It should be equal and not hopeful; it’s definitive!
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Here’s an example of some of the expectations in action.
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It’s very direct with things like 'must raise', 'must include', and 'won't include'.
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These offer great clarity in your testing.
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Much of what we accomplish with assertions can be done simply, without any convoluted syntax.
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It’s quite refreshing!
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That said, if we compare this to TestUnit, we can create assertions that don’t affect your namespace.
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It allows us to assert truth or falseness without contaminating our object.
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You won’t find these methods on the objects you're testing.
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That approach garners extra respect for Ruby as a testing language.
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Many tests support mocking and stubbing.
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Who here does a lot of mocking and stubbing?
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Cool! The rest of you should do a lot of mocking and stubbing!
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Your tests will run significantly faster that way.
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Testing support in MiniTest is very basic.
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There are only about three real files involved.
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Let’s break this down further.
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You get a MiniTest mock: you can create a mock object.
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You can set expectations on it.
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The verify step ensures those expectations are met.
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You can also stub on an object with a stub block.
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We do the same thing; we have an instance of something and stub the method.
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These techniques are effective, allowing your tests to run smoothly.
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Ruby also excels in mocking and stubbing.
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Let’s create a struct that behaves as if it had a complex object.
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You can replace heavy network classes with a struct or an open struct.
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This allows for cleaner, simpler tests.
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This method fades away when the instance is disposed of.
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Many tests demonstrate that we don’t need a complex mocking system.
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It’s all built into Ruby!
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However, there are great mocking libraries available, like Mocha and FlexMock.
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These offer certain levels of convenience.
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You might feel inclined to write your own, but please don’t!
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Instead, go to Ruby Toolbox and check what's already been done.
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You'll find alternatives to save you time.
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Custom assertions are easily made in MiniTest.
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Who here has created custom assertions in RSpec?
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A few of you! MiniTest allows for this in a far simpler manner.
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For example, you might want to create an assertion called 'must_round_to'.
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You can simply open up the MiniTest assertions module.
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Create a new method called 'assert_rounded' or name it whatever you wish.
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Just ensure you assert that it's equal.
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This method returns true/false, and you can supply a message.
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Now, here's where it gets even more interesting.
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You have to do something with these methods created.
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MiniTest won’t put these assertions on your objects until you instruct it to.
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You do that by using the 'infect_assertion' method.
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It's more simple than you may think!
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So you can etch into numeric values, so that they can round.
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You're not concerned with how other data types manage that.
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We have a MiniTest, a spec equivalent, which is really straightforward!
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We can install a MiniTest spec Rails gem; there's one available.
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They do need some updates; users may find it somewhat lacking. If you know the author, encourage them!
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You can create a test helper with requirements as we insert more tests.
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It's straightforward, incorporating pending task checks and so forth.
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MiniTest expectations allow you to include effects in blocks.
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You can, and we generally assert methods for redirecting.
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You can implement type checks like 'must redirect'.
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You don’t have to call a myriad of responses—keeping your code clean.
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I'll reference the slides later; they'll have all these examples.
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There's a little rake task to set this up, which is a touch of low-hanging fruit.
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It's instant easy fixes that would benefit anyone learning about the gem.
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One of the nice things about MiniTest is you run tests with pure Ruby.
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This means you can avoid chains of commands.
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Use it directly in your Rails folder!
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You can seamlessly incorporate standard functionality into your tests.
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If you like guard, who here uses guard?
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You should be using it for everything!
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I rely on it for everything, even silly things.
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Okay, here's my guard file. It's integral for developing your test process.
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MGM provides neat enhancements that allow you to optimize testing.
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You simply don’t need to pass in special flags to obtain results.
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It optimizes the search for files and knows where to look.
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If you're active in Capybara, it has provisions too.
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In conclusion, it's a familiar syntax for those seasoned with RSpec.
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You likely picked it up quickly and went, 'I already know this!'
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95% of functionality inherent in RSpec lies within MiniTest!
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What’s happening in that extra 5% that requires hundreds of lines of code?
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MiniTest is incredibly lightweight! Look at my gemfile.lock.
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These show what RSpec requires—note how much is necessary in comparison.
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Ultimately, you won't need any extras installed outside of what's already present.
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Quickly benchmark RSpec against MiniTest.
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Generally, Rails testing is slower, while MiniTest has a better speed rating!
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And let’s be real: every second counts in development.
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So I urge you to explore testing solutions while prioritizing both effectiveness and efficiency.
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Please view the resources I recommend. Check my screencast site!
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There are references like, 'Perform MiniTest in Rails' which cover all the basics.
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You can obtain valuable information, and it’s all free at Ruby AU 2014!
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Now, any questions?
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Yes, sir! You asked about the 95% that MiniTest covers?
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The biggest component you're missing is the ability to tag tests.
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For example, with VCR, you want tags for tests to harness specific behavior.
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But, there's also a MiniTest gem out there that provides tagging functionality!
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It's not often I don't use it, but if you want it, the option is there.
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This shared expectation is an element of that 5%.
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For tasks that rely on these shared expectations, you can create a module that includes methods.
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Or you can develop your own custom assertions for those needs.
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That's important to know! Anyone else have questions?
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Yes, one more question—kindly hurry as we are running behind!
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Does MiniTest work well with CI tools like Travis?
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Yes! It can run any Ruby-related tasks efficiently!
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Josh could answer this better than I could.
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Travis runs successfully with MiniTest!
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So, thanks everybody for your time today. I appreciate it!
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