public function testSecondaryMembership()
 {
     $products = $this->electronics->ProductsShowable();
     $this->assertDOSEquals(array(array('URLSegment' => 'hdtv')), $products, 'Should initially contain only direct membership products');
     $this->socks->ProductCategories()->add($this->electronics);
     $this->socks->write();
     $products = $this->electronics->ProductsShowable();
     $this->assertDOSEquals(array(array('URLSegment' => 'hdtv'), array('URLSegment' => 'socks')), $products, 'After adding a category via many-many to socks, that should show up as well');
 }