JUnit tests for known issues, part 2

A few days ago I considered different options for including known issue test cases (ones that you expect to fail) in a JUnit test suite in a way that wouldn't make the full test suite fail. I decided to adopt a solution that uses system properties to selectively enable such known issue test cases. Here's how I implemented it for Apache Jackrabbit using Maven 1 (we're currently working on migrating to Maven 2, so I'll probably post Maven 2 instructions later on).

The first thing to do is to make the known issue tests check for a system property used to enable a test. The example class below illustrates two ways of doing this; either to make the full known issue test code conditional, or to add an early conditional return to skip the known issue. You can either use a single property like "test.known.issues" or different properties to allow fine grained control over which tests are run and which skipped. I like to use the known issue identifier from the issue tracker as the controlling system property, so I can selectively enable the known issue tests for a single reported issue.

public class ExampleTest extends TestCase {

    public void testFoo() {
        if (Boolean.getBoolean("ISSUE-foo")) {
            // test code for "foo"
        }
    }

    public void testBar() {
        if (!Boolean.getBoolean("ISSUE-bar")) {
            return;
        }
        // test code for "bar"
    }

}

Once this instrumentation is in place, the build system needs to be configured to pass the identified system properties to the code when requested. In Maven 1 this happens through the maven.junit.sysproperties setting in project.properties:

maven.junit.sysproperties=ISSUE-foo ISSUE-bar
ISSUE-foo=false
ISSUE-bar=false

This way the known issue tests will be skipped when normally running "maven test", but can be selectively enabled either on the command line ("maven -DISSUE-foo=true test") or by modifying project.properties or build.properties.