27 November 2012

See the new test fail

The Wikipedia article about Test-driven development describes the process of TDD. It says that after adding a new test, you should run all tests and see if the new one fails. This is part of the red-green-refactor cycle. During my remote pairing activities with Thomas I noticed that I tend to forget this step. To fix this I wrote a tiny Eclipse plugin that complains if a test run does not fail after adding a new test.

Alert! New Test Did Not Fail
The plugin attaches itself to the org.eclipse.jdt.junit.testRunListeners extension point and records the names of all tests during JUnit test execution. (See RedGreenListener.java) When the test session is finished, it compares these test statistics against the previous run. In fact the only thing we need to know is if any test cases have been added. (See TestStats.java) Based on the comparison the plugin decides if to show an annoying popup or not. (See TestRunDiff.java)

The current mechanism is simple and likely to be wrong for special cases:
public boolean firstTestOk() {
    return newAdded.size() == 0 || secondFailed;
but it works great on katas and small hobby projects.

The org.eclipse.jdt.junit.testRunListeners extension point is available in Eclipse Europa (version 3.3), but it does not work there. The schema testRunListeners.exsd for the extension point seems to be missing from the JDT/JUnit bundles. The situation changes in Helios (3.6) and JUnit starts to notify the declared listeners. As the current release of Eclipse is version 3.8/4.2, I believe that two versions of backwards-compatibility should be enough.

Download the plugin here. Copy it into your plugins folder and restart Eclipse.

23 November 2012

BaDaDam Testing Framework

DIY Cable ReleaseSome time ago I had a look into BDD - no, not Bullshit Driven Development ;-) - but Behaviour-Driven Development. I started with JBehave but it seemed heavyweight to me. Further it had more than ten dependencies to other libraries, some with possibly problematic licences. Still I wanted to know how that kind of framework worked, so instead of learning by taking it apart I decided to build my own.

For some time I struggled to find a nice name for the project and discussed my problem with Michael. I was mumbling as usual and he mistook BDD as BaDaDam. Voila - I present to you BaDaDam, a minimalistic BDD framework for Java. Obviously it follows the spirit of JBehave, is lightweight, self sufficient and depends only on JUnit. It allows you to write stories in plain text, implement them in Java classes and run them using JUnit. The first version is finished since some time and available in my Maven repository here.