public function test__mapByPv()
 {
     /** === Test Data === */
     $DATA = [['CustId' => 1, 'PV' => 10], ['CustId' => 1, 'PV' => 20]];
     /** === Mocks === */
     $mLogger = $this->_mockLogger();
     $mToolbox = $this->_mockToolbox();
     $mCallDownlineSnap = $this->_mockFor('\\Praxigento\\Downline\\Service\\ISnap');
     /**
      * Prepare request and perform call.
      */
     /** @var  $sub Calc */
     $sub = new Calc($mLogger, $mToolbox, $mCallDownlineSnap);
     $data = $sub->_mapByPv($DATA, 'CustId', 'PV');
     $this->assertTrue(is_array($data));
 }