public static Test suite() {
        TestSuite suite = new TestSuite("org.jfree.data.category");
        suite.addTestSuite(CategoryToPieDatasetTests.class);
        suite.addTestSuite(DefaultCategoryDatasetTests.class);
        suite.addTestSuite(DefaultIntervalCategoryDatasetTests.class);
        suite.addTestSuite(SlidingCategoryDatasetTests.class);
        return suite;