public function testIsNullFilter()
 {
     MySql::executeStatement("TRUNCATE TABLE tblCompany");
     $company = new \Rhubarb\Stem\Tests\Fixtures\Company();
     $company->CompanyName = "GCD";
     $company->save();
     $companies = new Collection('Rhubarb\\Stem\\Tests\\Fixtures\\Company');
     $companies->filter(new Equals("CompanyName", null));
     $this->assertEquals(0, $companies->count());
     $companies = new Collection('Rhubarb\\Stem\\Tests\\Fixtures\\Company');
     $companies->filter(new Equals("ProjectCount", null));
     $this->assertEquals(1, $companies->count());
 }