public function testGetCategories()
 {
     $categories = $this->object->getCategories();
     self::assertTrue(is_array($categories) || $categories instanceof Countable, 'categories can be counted');
     self::assertEquals(1, count($categories), 'exactly one category assigned');
     self::assertEachIsInstanceOf($categories, 'Tx_CzSimpleCal_Domain_Model_Category');
 }