The Purpose Alignment Model

When scaling Agile/Scrum, we invariably run into the alignment vs. autonomy problem. In short, you cannot have autonomous, self-directing teams if they have no clue what direction they should go. Or, even shorter, alignment breeds autonomy.

But how do we create alignment? And what tools can we use to quickly evaluate whether or not what we want to do is part of the mission? Niel Nickolaisen, chief technology officer at OC Tanner, created the purpose alignment model. I use it with innovation labs in large enterprises to determine what aspects of innovation to keep, and what to leave to others.

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Filtering objects to Optionals

A while ago I stumbled upon a Blog post by Natascha the Robot about Configuring a Constant Using Shorthand Argument Names in Swift. Which by itself is a great post, but I was most inspired by the Then library mentioned at the end of her post. Seeing how such a small amount of code could change the way we configure constants everywhere gave me the idea to create something in a very similar fashion. But instead of configuring a variable it’s used to filter one based on a condition. Because why should filter only be applicable to collection types?

The usage of it is extremely simple and very useful:

extension String: Filter {}

"12345".filter { $0.characters.count > 4 } // Optional("12345")
"12".filter { $0.characters.count > 4 } // Optional(nil)

Only very little code is required to make this work:

extension Filter {

    /// Allows filtering of non sequence types.
    ///     let label = UILabel().then {
    ///         $0.textAlignment = .Center
    ///         $0.textColor = UIColor.blackColor()
    ///         $0.text = "Hello, World!"
    ///     }
    public func filter(@noescape condition: Self -> Bool) -> Self? {
        return condition(self) ? self : nil


extension NSObject: Filter {}

Not enough code to make a library out of it in my opinion. Just copy this code into your project. I did create a GitHub Gist which I will update if needed.

With this code, any object that inherits from NSObject will work by default. For pure Swift objects, just add the one liner to let the object adhere to the Filter protocol.

I’d love to hear your comments and hear about alternatives to this.

Keeping dependencies up-to-date in Maven

Keeping your dependencies up-to-date is more important than ever in modern projects. Everything is connected to the internet and needs to be secure. New vulnerabilities in libraries are found, exploited and patched within days. We use a lot of dependencies, and due to continuous delivery some of your dependencies will need updating every day. Solid dependency management is a primary requirement for good software.

In this blog post I will describe how to keep a Maven project up-to-date with the versions plugin. Using the versions plugin has a lot of benefits and configuring it takes less than an hour. So I suggest using it for all maven projects.

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Generic JS Android API wrapper for React Native

During a React Native project for one of our clients we added some custom Android and iOS libraries to our code and wanted to call a few exposed methods. In such a case, React Native requires you to write a wrapper class to call those public APIs. It was a small boilerplate nuisance and these wrappers would be unnecessary if we made a generic method call bridging API. Also, using such an API wrapper you can call any (obscure) available Android API that is not wrapped yet. Let's see how far we can get!

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Refactoring to Microservices - Introducing a Process Manager

A while ago I described the first part of our journey to refactor a monolith to microservices (see here). While this was a useful first step, a lot can be improved. I was inspired by Greg Young's course at Skills Matter, see CQRS/DDD course. Because I think it’s useful to reflect on the steps you take when changing software architecture, I’ve set a couple of milestones and will report on each when I get there. The first goal is to introduce process in our domain and see what happens.
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Including custom Flume components in Cloudera Manager

I'm currently working on a Hadoop project using Cloudera's stack. We're running a couple Flume jobs to move data around our cluster. Our Flume Metric Details page in Cloudera Manager looked like this:


You could infer from the image that we run a BarSource alongside our FooSource and BazSource and you would be correct. However, it doesn't show up in Cloudera Manager. Why not?

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Mapping Biases to Testing: the Anchoring Effect

Dear reader, welcome back to the Mapping Biases to Testing series. Today it is my pleasure to discuss the first bias in this series: the Anchoring Effect. Before we start mapping that to testing, I want to make sure that we have a clear understanding of what the anchoring effect is. 

Anchoring is a cognitive bias that describes the common human tendency to rely too heavily on the first piece of information offered (the "anchor") when making decisions. During decision making, anchoring occurs when individuals use an initial piece of information to make subsequent judgments. Once an anchor is set, other judgments are made by adjusting away from that anchor, and there is a bias toward interpreting other information around the anchor. For example, the initial price offered for a used car sets the standard for the rest of the negotiations, so that prices lower than the initial price seem more reasonable even if they are still higher than what the car is really worth.”

I highlighted the important parts. Decision making is something we constantly have to do during testing, and it is important to realise which anchors might affect you. Also, to make this clear, I think ‘testing’ is not just the act of doing a test session, but thinking about everything that involves quality. You can apply a testing mindset to all that is needed to make software: the process, the specifications, the way the team works, etc. Read more →

Automated UI Testing with React Native on iOS

React Native is a technology to develop mobile apps on iOS and Android that have a near-native feel, all from one codebase. It is a very promising technology, but the documentation on testing can use some more depth. There are some pointers in the docs but they leave you wanting more. In this blog post I will show you how to use XCUITest to record and run automated UI tests on iOS.
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FitNesse in your IDE

FitNesse has been around for a while. The tool has been created by Uncle Bob back in 2001. It’s centered around the idea of collaboration. Collaboration within a (software) engineering team and with your non-programmer stakeholders. FitNesse tries to achieve that by making it easy for the non-programmers to participate in the writing of specifications, examples and acceptance criteria. It can be launched as a wiki web server, which makes it accessible to basically everyone with a web browser.

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Profiling zsh shell scripts

With today's blazingly fast hardware, our capacity to "make things slow" continues to amaze me. For example, on my system, there is a noticeable delay between the moment a terminal window is opened, and the moment the command prompt actually shows up.

This post explores how we can quickly quantify the problem and and pinpoint the main causes of the delay.

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