Dr. Dobb's Journal - March 2008 - (Page 32)

Core Technology CHANGE CODE WITHOUT FEAR continued from page 30 crontab on UNIX. This process then regularly scans the project and generates more test cases for new and updated code, and executes all tests that comprise the regression suite, then reports all failures and cumulative coverage information. This report can be e-mailed to individual developers, or they can import it directly into their IDE—effectively triggering their review of the failures and the new/changed code. This cycle is then repeated every time the regression process is run. This one-time process scans the project and generates a test class for each Java file in the project. In the JPetStore example, 40 new test classes containing 702 test cases were generated. The tool proceeded to execute only these automatically generated test cases because the regression test suite did not include any manually written test cases. It reported coverage of 91 percent of the source code: [exec] Executed Test Cases: 702 [exec] Runtime Exceptions: 0 [exec] Assertion Failures: 0/0 verified [exec] Contract Violations: 0 [exec] Profiling Problems: 0 [exec] Unverified Outcomes: 0 [exec] Coverage: [exec] Line: 91% [994/1090 executable lines] Extending the Test Suite Before extending the test suite, it’s helpful to review the automatically generated test cases. For example, Listing One is a sample test that’s automatically generated for the com.ibatis.jpetstore.domain.Order class (specifically, its initOrder() method). Notice how the tool automatically generated input data to use for the test. At the same time, it created assertions based on the observed state of the objects at the end of the test. This now becomes a test that you can always rerun against the Order class to confirm that its behavior remains intact as you are extending and modifying it. Further, you can extend the automatically generated test suite either by manually adding more test cases or by modifying the automatically generated tests to use realistic data, check specific assertions, or test various functional scenarios that you may be interested in. Here is an example of a test for the initOrder() method in the com.ibatis.jpetstore.domain.Order class. Listing Two (available online; see Resource Center, page 5) is a test created by manually extending one of the automatically generated tests to add more logical, realistic data—as well as to add more assertions. Over time, you might want to further improve the intelligence of the regression test suite by using automated tools that record interactions with a running application, then produce functional JUnit tests representing the recorded interactions. Listing Three (available online) is an example of a front-end JUnit test that represents a scenario of purchasing a dog and a cat, then validates that the total for this order is $112. Building a Behavioral Regression Test Suite To demonstrate this process, I use Parasoft JTest to create a Behavioral Regression Test Suite for the JPetStore 4.0 project from iBatis (sourceforge.net/project/showfiles.php? group_id=60632). This is a simple web application that lets you purchase pets online. First, automatically generate an initial regression suite for the JPetStore project. Next, set up the automated testing tool to run using Ant. The appropriate Ant properties are configured to point to the tool installation directory and the Eclipse workspace (which is where the JPetStore project is located); for example: Responding to Reported Failures Imagine that this process has been running for about 30 days, and that the development 32 Dr. Dobb’s Journal l www.ddj.com l March 2008 http://sourceforge.net/project/showfiles.php?group_id=60632 http://sourceforge.net/project/showfiles.php?group_id=60632 http://www.swellsoftware.com http://www.swellsoftware.com http://www.ddj.com

Table of Contents Feed for the Digital Edition of Dr. Dobb's Journal - March 2008

Dr. Dobb's Journal - March 2008 Contents Hmmmm Alia Vox Developer Diaries Developer’s Notebook Social Networks and Software Development Conversations Detecting Bugs in Safety-Critical Code Change Code Without Fear Continuous Integration and Performance Testing Wt: A Web Toolkit Automating Release Notifications The Agile Edge Effective Concurrency Swaine’s Flames

Dr. Dobb's Journal - March 2008

For optimal viewing of this digital publication, please enable JavaScript and then refresh the page. If you would like to try to load the digital publication without using Flash Player detection, please click here.