Improve your Feedbackloop with Continuous Testing

Have you ever though about what the most valueable thing in software development was for you? And im not talking about things that value for you personally, but for the success of the development itself. Well i have thought about it, and for me it was Feedback - in any form. It is so important, because it enables steering. Development practices are made for the purpose of better feedback. TDD, Continuous Integration, Iterations, to name only a view. Many of the agile methods and XP are basically about better feedback.

It begins with customer interaction. I need as much feedback as possible, as frequent as possible. If i don't get feedback, i'm likely to get on the wrong track, resulting in a product that is not going to be used, because it's not what the customer needed. The more feedback i get, the better the outcome will be. If i get feedback rarely, i am unable to steer. I'm forced to make assumptions which are likely just obstacles. The quicker i get feedback, the faster i can deliver value to my customer. Feedback allows me to steer.

Feedback is as important for programming. I want it early and often. If i write hundreds of lines of code without running them, they will most likely result in a very long and painful debugging session, and a lot of changes. I don't want that, so i take baby steps. They make me go safer, faster and happier. There are two phases that define my programming feedback loop.
  1. The phase where i write code. Lets call it alpha, like so 'α'.
  2. The phase where i evaluate my code, and eventually fix errors. Lets call it beta, like so 'β'.
You could also see those phases as modes. It is important to understand here, that these phases have nothing todo with the alpha/beta definition of a software cycle. I just invented them to describe my programming feedbackloop.In the following graphics you'll notice that the lines get shorter and shorter by example which is intentional and should point out how i got faster using new strategies.
    When i first started coding, i did not write any tests. I wrote lots of code before i tried it out manually. Obviously it didn't work when i first ran it. I ended up in rather long α-phases, where i just wrote code, and also long β-phases, where i evaluated (got my feedback), and fixed it. Like this:



    I was very slow back then.

    I soon started with an interpreted language, which was very cool because i could run the scripts immediately. No need to compile or anything. Just write and run. It shortened my feedback loop, and i became faster overall:



    Sooner or later i eventually started tdd. And regardless of the language that i was using, interpreted or not, it again shortened my feedback loop and made me go faster. The loop was shortened to a single 'unit', which is obviously smaller than anything manually executable. It allowed me to evaluate small behaviours, long before the program was even runnable. It is important to understand, that the α-phase in the following graphic contains both writing tests and implementation. The β-phase is much shorter, since unittests run very fast.


    I thought this was just great, and it could not get any better. Wrong i was!! Later, i tried something that made me go like this:



    "What the ...?" You might ask. No, i did not break space-time. The thing i tried was Continuous Testing. Which basically means, that i do tdd, but i don't run my tests by pressing a button and then wait. I just have them run all the time in the background automatically... Everytime i change my code, my tests immediately run automatically, and show me "OK" or "NOT OK" on a small icon on my screen. Since the tests only take about a second to run, this feedback is instant. And since my IDE saves my files onchange automatically, i do not have to press ctrl+s or anything. I just code... and as i code my files get saved.... and as the files get saved my tests get run... fluently, immediately. This is HUGE. I am now progressing without disruption. I completely broke out of the phases, or if you want to call them 'modes'. I love it.

    I have used infinitest for this. It is a Continuous Testing plugin for Intellij/Eclipse. If you are doing javascript, i can also recommend grunt for Continuous Testing.


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    About the „Is TDD Dead?“ discussion

    It did not take long after Agile died that TDD joined its party. If you havent noticed, David Heinemeier Hansson put up quite a rant against TDD on his blog leading to a lot of discussion - also on Twitter. Finally they ended up doing a live online discussion regularely featuring Kent Beck, Martin Fowler and David not (yet) involving the TDD advocate Robert C. Martin aka uncle bob. If you haven't watched it live, here is the initial 30min discussion of the series on Youtube. I really recommend the whole series.

    I think this topic and the ongoing discussion is very valueable to our craft because it is the kind of questioning and critical thinking that evolve what we do and how good we are at it. Even if we have a strong faith in something, we should not be afraid to question it, ever.

    I get davids points, however i do not entirely agree with all of his concerns. I want to share my thoughts in this blogpost.

    „Test induced design damage“
    A good design is a design that makes the software easy to change. I think this is something we all agree about. While TDD generally puts a lot of good pressure on the design, if you're not careful you're going to couple the tests tightly to the structure of your code. In this case even refactorings might force us to touch a lot of test-code aswell. You don't want that to happen. Tests should be the enabler of refactoring. I've happened to experience lots of applications that were so small that sociable unittests with reduced mocking and integration tests were just perfect. The value of this approach was that it was very easy to change/refactor production code without touching test-code. TDD does not solve these design problems, TDD does not design for you. TDD is just a design tool, but you are still the designer. Testing is engineering. Look for advantages, make tradeoffs. Trying to minimize mocking can definitely pay off.
    To Test first, or not to Test first
    The point is, you do not want to verify if the code is working manually. You'd have to do it way too often, and it would just take too long. You want to be able to fiddle with the code, and do small changes frequently, without having to try everything out manually. You want to do it automated and the feedback should be instant. So i see no point in 1. writing code, 2. trying it out, and then 3. writing a test. Why not write the test in the first place? Also, we tend to be very flaccid on writing a test for something that we have found to be working, because we tend to become euphoric about our success quickly which makes us tired of digging in details later. Other than that, the actual writing of the test first forces us to think about the problem to an extent that makes us recognize hidden details. These details are better be known before we start writing the code.

    TDD is so widespread nowadays
    I was laughing when i noticed that there are actually people who believe that everyone does tdd nowadays. Sadly, TDD, or lets say developer testing is in fact unused and/or undiscovered in many places. I've happened to see it missed in programming education and also software companies. Sometimes, it was even unwelcome. If you were using any kind of developer testing in these places, you were a pioneer. There is still plenty of work to do on this topic.

    The bottom line is, automated developer testing is good. We need it. We were silly if we didn't.


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    An Annotation Nightmare

    @XmlElementWrapper(name="orders")
    @XmlJavaTypeAdapter(OrderJaxbAdapter.class)
    @XmlElements({
    @XmlElement(name="order_2",type=Order2.class),
    @XmlElement(name="old_order",type=OldOrder.class)
    })
    @JsonIgnore
    @JsonProperty
    @NotNull
    @ManyToMany
    @Fetch(FetchMode.SUBSELECT)
    @JoinTable(
    name = "customer_order",
    joinColumns = {
    @JoinColumn(name = "customer_id", referencedColumnName = "id")
    },
    inverseJoinColumns = {
    @JoinColumn(name = "order_id", referencedColumnName = "id")
    }
    )
    private List orders;

    Wait. What? Is this really what we have come to? I can't even see the damn property under this bloat. How did this happen? Yeah ok - we had to get rid of the old xml configuration horror somehow. But this? This is even WORSE. This class is supposed to be a goddamn pojo with a bunch of properties. Short and concise, easy to read. I, as a reader of this cass, am not interested at all how the database table is joining customers to orders. I'm neither interested how its being serialized. This is just implementation details. Reading this class, i am living in an object world and i want to know what data and behaviour the object has. Not more, not less. I don't care about column names, fetchtypes or json serialization for the moment. And i don't want to read, change or recompile this class for the sake of a tablename change. I don't want to add another annotation for storing this entity in a mongoDB neither. The entity should not have responsibility for these details. We are not only violating the Single Responsibility Principle here, we are doing a f****** responsibility party.

    Ok ok, enough of the rage. How do we deal with this issue? Some duplicate the entity for various layers with different annotation purposes. They map the entity onto the next layers related entity using an automated mapper like Dozer. Some even write that mapping themselves. But this is by no means a solution. It is just replacing one code smell with another one: Duplication.

    So please, focus on frameworks that don't force you to clutter your code. jOOQ is a nice solution to map database records to entities without annotations. Also, hibernate allows you to define your mappings in XML.

    Private Field Injection


    @Inject
    private MyService myService

    This is used quite often, while it shouldn't even be possible. The myService field is private, thus it's inaccessible from outside the class. Nevertheless it's possible and people do it. In reality it is a hack. The DI-framework sets the field using reflections doing setAccessible(true). You don't want hacks in your code, do you? Lets have a look at the alternatives:

    Setter Injection
    Well, at least its better than the private field injection, since its using a public method instead of hacking a private field. But still, ask yourself this: 'Is this class even supposed to live without the injected value?' Because if it's not, there is no reason what so ever for the class to get constructed without an instance of MyService. You want to implement this constraint on the class level and inside the constructor, not on the framework level.

    Constructor Injection
    This is usually the way to go. It allows you to
    • make the field immutable (there is usually no need to change it).
    • implement the constraint, that the class is not instantiatable without a given MyService in the right place.
    Of course it means that you cannot inject by annotation. But why would you want to? The class doesn't need to know, if it gets injections by a DI-Container or a Factory Class. It should not know anything of this. No @Autowired, no @Qualifier. All it needs to know is its own behaviour. Everything else should be handled outside of the class.
    One could use a configuration class or file for the actual injection.

    A DI-Container is a usefull tool that helps you wire your classes together. Use it for this purpose, but don't let it dictate your code. Uncle Bob wrote a great post where he explained how to use DI-Frameworks without having them dictate your code.

    @RunWith(SpringJUnit4ClassRunner.class) in UnitTests

    Why would you need this in unittests? Because it is automatically generated by your IDE/app template? No! You want to test the behaviour of a class, living in isolation in unittests. Not if the DI-Conainer is injecting a fields accordingly. Just inject yourself in a setup method. No DI-Container needed. By the way, all this testrunner does is these 3 lines of code.

    private TestContextManager testContextManager;
    //..
    this.testContextManager = new TestContextManager(getClass());
    this.testContextManager.prepareTestInstance(this);

    They are not worth blocking your only TestRunner slot. You want to keep it free for something like parameterized @RunWith(JUnitParamsRunner.class) or concurrency @RunWith(ConcurrentJunitRunner.class) tests.

    tl;dr
    Annotations have become more harmful than helpful these days. We should get back to pojos and focus on keeping our code as clutterless and framework-agnostic as possible to make it more readable and reuseable. Don't let frameworks dictate your codebases, since they should be exchangable tools. Beware of what a class should know, and what not. Some annotations are useful, most aren't.

    @DevNull({
     @SuppressWarnings
     @Autowired, 
    @Inject, 
     @Override 
     @XmlElementWrapper,
    @XmlJavaTypeAdapter,
    @XmlElement,
    @JsonIgnore,
    @JsonProperty,
    @ManyToMany,
    @Fetch,
    @JoinTable
    })


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    Sessions, a Pitfall.

    I got asked quite often, why one shouldn't use sessions and whats so bad about them. In this post i want to sum up my thoughts and experiences.

    Sessions produce unnecessary complexity

    The term bugfoot is a combination of bug and bigfoot. It's used for a bug that appears only once and is not reproducable. A bugfoot tells you that something is wrong, and that it will probably come up again. But you cannot fix it, because you don't know the cause.

    If you want bugfoots in your software, just use sessions. Sooner or later you'll happen to see one.

    Sessions don't scale

    Lets say you are a professional chess player, and you'd like to play multiple people at the same time. If you'd try to remember every game and your strategy on it, you'll hit your capacity rather quick. Now imagine you were not remembering anything of those games, and you were just rereading the chessboard on every move. You could literally play 1.000.000 people at the same time, and it wouldn't make any difference to you.

    Now draw an analogy to your server. If your application gets a lot of load, you might have to distribute it to different servers. If you were using sessions, you'd suddenly had to replicate all sessions to all servers. The system would become even more complex and error prone.

    Sessionstate cannot be bookmarkable nor cachable

    Did you try to bookmark your shopping cart? Nah, of course you can't because it's empty as soon as the session runs out. Imagine a shop that actually allowed you to bookmark your cart. Like
    • http://example.com/carts/1337 or
    • http://example.com/cart?products=[{id:1, amount: 1}]
    How wonderful that would be.

    Conclusion

    You want a simple system that is easy to test and whose bugs are easy to reproduce. State leads to the opposite. HTTP was never ever ment to be stateful and it should have stayed this way.

    If you want some rest, follow these two rules
    • Keep all application state (not resource state) on the client
    • Keep all shared state (not session state) on the server


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    Boost your development speed

    I'm really pragmatic on this. To go faster, you need to avoid the things that slow you down. These blockers may vary from developer to developer, but some are pretty common. In this post i will elaborate on the more common ones. Before i do so i want to remind you that to improve, we might need to unlearn in the first place.
    Tip: Sometimes, the greatest achievement in improving is to successfully unlearn.

    Are you using your Mouse?

    Don't let your mouse slow you down. If you are not using all of your fingers typing, you might want to stop reading here and go over to a typewriting course. The following recommendation also assumes that you are using a feature rich editor like vim or an ide. Every single time you move your hand over to your mouse for a click there is a keyboard shortcut for the exact action that you are not aware of, or not used to. You want to learn these. It's really not that hard,  you'll get used to it faster than you'd think. Just begin by putting your mouse over to the other (or wrong) side of your keyboard. You're now forcing yourself to think every time you want to click. When this happens, remember to think of a possible solution using your keyboard. Don't know any? Ask your friends or search the internet (yes, you can use your mouse for that). BUT: Do not use your mouse for what ever action you wanted to perform. After following these simple rules for a few days, you'll notice how irrelevant your mouse has become. If you start feeling comfortable using your keyboard only, you could even try some sessions with your mouse plugged out. Mastering your keyboard will significantly boost your development speed.
    Tip: You could print out a list of your IDEs shortcuts and use it as a cheatsheet

    Reduce the Time debugging

    Debugging costs an awful lot. It's not rare that we end up hunting a bug for hours or even days. Quite often we engage multiple co-workers to solve it. This is really not a scenario we want to be in, since its not only expensive, but also depressing. How can we avoid such a scenario? Pretty easy. Just separate the software into pieces that work in isolation, and write automated tests that cover the components behaviour. This way, we can easily distinguish the component the bug is actually sitting in, and the debugging will become a cinch. The better the tests, the easier to find the bug. However, you wont write good tests, if the system that you are testing is already done and working. You'll assume that there is no additional value of writing thoughtout tests, when it's already working. Overcome this dilemma by writing your tests BEFORE the implementation. As a side effect, this will also help you coding in many ways. You want to treat your tests as first class citizens and as what they are - at least as important as your implementation. Think of a blacksmith who's casting metal into a mold. What would be more important for him. The mold, or the first sculpture coming out of it? You know the answer. And guess what... the tests are your mold. I don't care what you call it. TDD, BDD or whatever. Just automate tests to cover your softwares behaviour, write them before the implementation, and treat them as what they are - at least as important as your implementation.
    Tip: When using TDD, you want to use a shortcut to quickly navigate between the test and its implementation. I've bound it to Alt+T


    Reduce the Time reading code

    I can't stress this enough: You spend more time reading code than writing code. Believe it or not, while implementing a new feature or solving a bug, you repeatedly read code. You read code before you start writing new code, you read code multiple times inbetween writing code, and you read code after you have written it. Reading a 50 line method is pretty time consuming. Thus you want to make reading as easy and smooth as possible. Write self explanatory code with good names and short methods. And Don't Repeat Yourself. Who wants to read anything twice? Invest some time on this, and it will pay off.

    Improve your search skills

    This is an important one. A searchengine has become the most important development tool. It is even more important than your ide. You can do anything without your ide if you can find out how, but you cannot do anything with your ide if you dont know how. You are probably googling regularely, so it's worth improving. Improve your searchterms. Anticipate helpful words like 'how to' or 'problem'. Try different variants and quote important words and sentences. If you keep getting bad results of a common subject or website, filter them out using a preceeding minus. Here are some examples:
    • while c -do -c++
    • SomeException -helpme.com
    • How to "clean code"
    If you keep getting out-dated information, limit your search to the last month/year. This can easily be done in the search options. On stackoverflow, do not always read the first post since its usually a question and code thats not working. Scroll down to the answers with the most upvotes. They are worth reading. Bookmark the sites/docs that you are using regularely. You don't want to search them over and over again. Also, consider code search engines (Examples here and here).


    Focus & Calm

    You want to get into and keep a good focus when working on a task. Get into your flow and do not allow disruptions. Several disruptions can easily cost you an hour or two each day. Use headphones in louder environments, and communicate that you'll be available for questions a little later. Focus requires a clear mind. Make sure you don't have to remember too much stuff. You don't want to be afraid of forgetting things. If you can feel the fear to forget, write that thing down - so you can forget. Also, don't work on too many different tasks/projects at the same time. One is perfect, two is ok. More is probably just slowing you down. I've happened to work on 7 different projects a single day. It's really really dragging from you. Also, stay calm even in the most stressful situation. Huddling just slows you down even more.

    Invest in Hardware

    Hardware is cheap, workhours are not. Good hardware will save lots of time in the long term. An SSD that makes you boot within seconds and loads everything real quick, saves at least 10 minutes a day which is 40 hours a year. Same goes with ram and cpu of course. Also, screensize really matters. Choose a large monitor to be able to see everything without resizing/scrolling windows/panels. I personally feel comfortable with ~27". You can speed up many tasks using two monitors also. Web development would be such a task for example.
    Tip: 16:9 is standard nowadays but not quite optimal for coding. The higher the screen, the more lines of code you see. Try a 16:10 instead.

    Optimize your Workflow, Question your Tools

    It depends on what you are working on, but the goal stays the same. You want the most lean workflow and you will constantly have to reevaluate and improve it. For example: If you are working on a Java Webapp, you want to be able to quickly get feedback without redeploying. You can do this by using a class-reloader like spring-loaded or JRebel, or use the Play Framework which does not require redeployments at all due to its architecture. You could also question the language. Is there something else than java that could be more appropriate? Automate everything: testing, building, deployment, notifications. Consider rapid prototyping if you are in the early stages of a project.



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