What is a good test?

A colleague asked that question the other day. What is a good test? It is a really difficult question to answer. There are a number of properties that hold true for a good test. I will list some of them and discuss why I think they are important. Others may think that the order of importance is different or that other properties are more important then those that I list.

I will show some examples using Java and JUnit of what I think are bad tests and how they can be refactored to something better.

Tests are automated in my world. I always try to avoid manually testing. The main reason for this is that manual testing is slow and hard to repeat arbitrary many times. Therefore, test should be read as automated test in for the rest of this text.

Testing a Web Service with SoapUI, JUnit, Maven and Cucumber

An example is perhaps the best way to describe something. Concrete examples are easier to understand then abstract descriptions.

I will show how SoapUI can be used to test a web service. I will also show three different tools that can be used to control SoapUI. This tool chain can easily be made a part of your continuous build.

What is the difference between i++ and ++i?

During a coaching session I got a question about a loop.

Would there be any difference in the output from a loop defined as

for (int i = 0; i < 3; i++) {
    System.out.print(i + " ");
}

and a loop defined as

for (int i = 0; i < 3; ++i) {
    System.out.print(i + " ");
}

in Java?

Magic numbers

The other day a colleague asked me, what is a magic number? He had noticed that one of the things our Sonar was complaining about was Magic numbers. I got a great teaching moment and told him my view of Magic numbers.

Magic numbers are any numbers in the source code that just appears without any explanation.