Property-based testing in Java with JUnit-Quickcheck - Part 1: The basics
To be able to show you what Property-based testing (PBT) is, let's start by grasping the concept of a property in programming languages. Since this is a Java tutorial, I will start with Oracle and their definition of a property in their glossary:
Characteristics of an object that users can set, such as the color of a window.
Property is neither a variable/field or a method; it is something in between which is always true in your context. An example is weight in a postal parcel: this always is greater than zero. In Java the following example implementation would follow:
Breaking changes in Swift 4
Refactoring to Microservices – Using a Document as State
In a previous installment of our Microservice refactoring effort, I’ve introduced a ShopManager and a Clerk to implement the shopping process (see this blog). I ended up with a JSON document transferred between services. To make life easy for myself I just parsed all of the document using Spring magic. This time I will discuss the downside of this strategy and show an alternative.
Why microservices fail
Gianna has joined Avidoo Inc., a productivity platform, as a senior software engineer. In a kick-off meeting with the rest of her team, she brings up the subject of microservices and whether the team has adopted them in any way. She immediately gets a strong reaction.
“We have tried adopting microservices, but they don’t work”, Byron offers.
“It became a terrible mess!”, Kary adds.
Gianna blinked her eyes three times expecting some kind of elaboration, but none followed.
After an uncomfortable silence, Gianna asks: “So what happened?”
“At first it was great. Every time we were asked to create something new we had the opportunity to add a service and use whatever languages and frameworks we wanted to experiment with. We exposed REST APIs on systems it needed to collaborate with or worked on their databases directly. But after a while, things started to break more and more often and development slowed to a crawl.”
Gianna sighs. It sounds to her like her team had been building a distributed monolith, while what they had meant to build were microservices.
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Eight Characteristics of Successful Software Projects
We do a lot of software projects at Xebia Software Development. We work most of the time at our client’s location, in their teams. Together we improve the quality of their software, their process, and engineering culture. As such, we’ve seen a lot of projects play out. Most of these efforts succeeded but some failed. Recently we did a retrospective to learn from these experiences. The result is this opinionated list of characteristics of successful software projects.
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Cheating and building secure iOS games
You probably have one of the million games where you earn achievements and unlock specials on your iPad or iPhone. If you develop games, you've probably wondered about people cheating your games? In this blog we're going to show you how to try cheating out yourself and how to build secure iOS games.Read more →
De-mystifying Jest Snapshot Test Mocks
So, let’s say you have a nice React Native setup with the Jest testing library. You want to snapshot-test all your components of course! But you’re getting seemingly unrelated errors when you tried to mock a third party module in your snapshots and you’re lost in all that API documentation. Let’s dig into an example and get a clear picture of what’s happening under the hood.
TDD is not about unit tests
-- Dave Farley & Arjan Molenaar
On many occasions when we come at a customer, we're told the development team is doing TDD. Often, though, a team is writing unit tests, but it's not doing TDD.
This is an important distinction. Unit tests are useful things. Unit testing though says nothing about how to create useful tests that can live alongside your code. On the other hand TDD is an essential practice for improving the design of your code. These are very different things.
Caveats and pitfalls of cookie domains
Not too long ago, we ran into an apparent security issue at my current assignment - people could sign in with a regular account, but get the authentication and permissions of an administrator user (a privilege escalation bug). As it turned out, the impact of the security issue was low, as the user would need to be logged in as an admin user already, but it was a very confusing issue. In this post I’ll try and explain the situation, how browsers handle wildcard subdomain cookies, and what to keep in mind when building an authentication back-end when it comes to cookies storing session information.