Agile 2007 Session: Learning Test-Driven Development (TDD)

I'll be presenting a beginner's session at the Agile 2007 conference this year. The session, titled "Learning Test-Driven Development," is intended to provide a brief hands-on introduction to TDD. More details are available at the conference site.

Here are the slides I plan on presenting; they are subject to change:
Slides

As the conference site indicates, the session is intended to be hands-on, but you can also just come to watch and learn. In either case, I'd like to make your experience as smooth as possible. It's a short program, so programming along will require solid developer skills and decent speed.

If you choose to follow along, you can go one of two routes: You can choose to code along as I type and talk, or you can download the test source. Just about everything in the test source is commented out, so you can follow along by uncommenting out lines in the test. (You'll still get to write the production code that we'll be test-driving!)

I'll be using Eclipse 3.3 for my demo, but you should be able to follow along in just about any environment. The demo will be done using Java 6 and JUnit 4.

Note: my session and demo emphasizes learning the techniques involved in doing test-driven development. While you will see most of what you'll need to know on JUnit, learning JUnit is secondary, and I will not be covering all its features. You can find a good reference on JUnit by doing a Google search.

Prerequisites

You will need Java version 5.x or 6.x, and JUnit version 4.x.

The below instructions are based on Eclipse 3.3. These instructions should be close to what you will need for earlier versions of Eclipse. Note that there are many ways to accomplish the same tasks using Eclipse!

If the Eclipse instructions do not work for you, or if you are using a different IDE, you should be able to copy the source files directly into your project (or folder, if you're running Java natively). The Manual Instructions below summarizes the steps you need to accomplish.

Eclipse Instructions

• From the Eclipse menu, select File->Import
• From the Import dialog, select General->Existing Projects Into Workspace
• Click the Next button
• Ensure that the radio button Select archive file is chosen.
• Click the Browse... button, navigate to Agile2007LearningTDD.zip, and select it. The list of Projects should show agile2007LearningTDD, and it should be selected.
• Click the Finish button.
• You should now have a project in your workspace named agile2007LearningTDD. From a Navigator view, select the project and right-click.
• From the context menu, select Run As->JUnit Test. You should see the JUnit view appear. The JUnit view should show Runs: 1/1, Errors: 0, and Failures: 1. In the Failures Trace pane, you should see something like:

  java.lang.AssertionError: to demonstrate JUnit failure
     at PortfolioTest.verifyJUnit(PortfolioTest.java:29)

Manual Instructions

• Copy the source files PortfolioTest.java and StockLookupService.java into your project or directory in which you will be building.
• Ensure that the JUnit 4 JAR is available on the classpath. If you are not using an IDE with JUnit support, you can find JUnit at http://JUnit.org.
• Compile!
• Execute JUnit against the test class PortfolioTest. You should see one test run with one failure. If your IDE does not support JUnit (or you are executing from the command line), here's an appropriate Java command that will execute the tests in PortfolioTest:

  java -classpath .;c:\ProgramData\junit4.4\junit-4.4.jar org.junit.runner.JUnitCore PortfolioTest
  

Suggested Reading Material

Beck, Kent. Test-Driven Development: By Example
Langr, Jeff. Agile Java: Crafting Code With Test-Driven Development
Link, Johannes. Unit Testing in Java: How Tests Drive the Code