CakePHP 3 TextFixture for many records

ChunkInsertTestFixture.php

<?php
namespace App\TestSuite\Fixture;

use Cake\Datasource\ConnectionInterface;
use Cake\TestSuite\Fixture\TestFixture;

/**
 * ChunkInsertTestFixture
 */
abstract class ChunkInsertTestFixture extends TestFixture
{

    /**
     * Insert records per this chunk size
     *
     * @var int
     */
    protected static $insertChunkSize = 1000;

    /**
     * {@inheritDoc}
     */
    public function insert(ConnectionInterface $db)
    {
        $generator = $this->recordGenerator();
        foreach ($this->chunkRecords($generator, static::$insertChunkSize) as $records) {
            $this->records = $records;
            if (!parent::insert($db)) {
                return false;
            }
        }

        return true;
    }

    /**
     * Divide the records per chunk size
     *
     * @param \Iterator $generator the insert records generator|iterator.
     * @param int $size a chunk size.
     * @return \Generator
     */
    private function chunkRecords(\Iterator $generator, $size)
    {
        $records = [];

        while ($generator->valid()) {
            for ($c = 0; $c < $size && $generator->valid(); $c++, $generator->next()) {
                $records[$generator->key()] = $generator->current();
            }
            if (count($records) > 0) {
                yield $records;
            }
            $records = [];
        }
    }

    /**
     * generate records
     *
     * @return \Generator|\Iterator
     */
    abstract protected function recordGenerator();
}

継承したクラスでの recordGenerator の実装はこんな感じ

    /**
     * @return \Generator
     */
    protected function recordGenerator()
    {
       for ($i = 0; $i < static::$numOfRecords; $i++) {
            $id = $i + 1;
            $record = [
                'id' => $id,
                'title' => sprintf('title_%06d', $id),
                'content' => sprintf('content_%06d', $id),
            ];

            yield $i => $record;
        }
    }