public function testIsTrunk()
 {
     $this->assertFalse($this->categories('Child 1')->isTrunk());
     $this->assertFalse($this->categories('Child 2.1')->isTrunk());
     $this->assertFalse($this->categories('Child 3')->isTrunk());
     $this->assertFalse($this->categories('Root 2')->isTrunk());
     $this->assertFalse($this->categories('Root 1')->isTrunk());
     $this->assertTrue($this->categories('Child 2')->isTrunk());
     $new = new Category();
     $this->assertFalse($new->isTrunk());
 }