public function testCount()
 {
     $company = new Company();
     $company->CompanyName = "a";
     $company->save();
     $company = new Company();
     $company->CompanyName = "b";
     $company->save();
     $company = new Company();
     $company->CompanyName = "b";
     $company->save();
     $company = new Company();
     $company->CompanyName = "a";
     $company->save();
     $collection = Company::find();
     list($companies) = $collection->calculateAggregates(new CountDistinct("CompanyName"));
     $this->assertEquals(2, $companies);
 }