Laravel test for aggregating analytical data on software

CalculateStatisticsCommand.php

<?php

use Illuminate\Console\Command;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Facades\Cache;

/**
 * Laravel command to calculate and cache logs statistics
 */
class CalculateStatisticsCommand extends Command {
  public function handle() {
    // accumulator of the counts batches
    $all_counts = collect([]);

    // loop log items (in batch) in order to count each country code
    // todo: possibly can be optimized to aggregate the json data in mysql itself (done in laravel for experimentation purpose)
    DB::table('logs')
      ->orderBy('id')
      ->chunk(500, function ($logs) use (&$all_counts) {
        // parses each log row and aggregates by country code
        $counts = $logs->countBy(function($log) {
          // todo: could be optimized to get countryCode from regex instead of parsing the whole json
          $params = json_decode($log->params);
          return $params->countryCode;
        });
        // stores aggregation count for this batch in the accumulator variable
        $all_counts->mergeRecursive($counts);
      });

    // sums aggregated values for final result (not sure the data format applies for mapWithKeys, would be sure by testing with a dataset :))
    $final_counts = $all_counts->mapWithKeys(function ($item, $key) {
      if (is_array($item)) {
        $sum = array_sum($item);
      } else {
        $sum = $item;
      }
      return [$key => $sum];
    });

    // stores the resulting data in the cache store
    Cache::put('statistics-logs-countryCode', $final_counts);
  }
}

StatisticsController.php

<?php

use App\Http\Controllers\Controller;
use Illuminate\Support\Facades\Cache;

class StatisticsController extends Controller {
  public function dashboard() {
    $countryCode = Cache::get('statistics-logs-countryCode');
    return view('statistics.dashboard', [
      'statistics' => [
        'countryCode' => $countryCode,
      ],
    ]);
  }
}