Introduce a reader that read from a value fetched by a parameter accessor

src/batch/src/Job/Item/Reader/ParameterAccessorReader.php

@@ -0,0 +1,38 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Yokai\Batch\Job\Item\Reader;
+
+use Yokai\Batch\Job\Item\ItemReaderInterface;
+use Yokai\Batch\Job\JobExecutionAwareInterface;
+use Yokai\Batch\Job\JobExecutionAwareTrait;
+use Yokai\Batch\Job\Parameters\JobParameterAccessorInterface;
+
+/**
+ * This {@see ItemReaderInterface} uses a {@see JobParameterAccessorInterface} to read data from.
+ */
+final class ParameterAccessorReader implements ItemReaderInterface, JobExecutionAwareInterface
+{
+    use JobExecutionAwareTrait;
+
+    private JobParameterAccessorInterface $data;
+
+    public function __construct(JobParameterAccessorInterface $data)
+    {
+        $this->data = $data;
+    }
+
+    /**
+     * @inheritdoc
+     */
+    public function read(): iterable
+    {
+        $data = $this->data->get($this->jobExecution);
+        if (\is_iterable($data)) {
+            return $data;
+        }
+
+        return [$data];
+    }
+}

src/batch/tests/Job/Item/Reader/ParameterAccessorReaderTest.php

@@ -0,0 +1,44 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Yokai\Batch\Tests\Job\Item\Reader;
+
+use Generator;
+use PHPUnit\Framework\TestCase;
+use Yokai\Batch\Job\Item\Reader\ParameterAccessorReader;
+use Yokai\Batch\Job\Parameters\JobParameterAccessorInterface;
+use Yokai\Batch\Job\Parameters\StaticValueParameterAccessor;
+use Yokai\Batch\JobExecution;
+
+class ParameterAccessorReaderTest extends TestCase
+{
+    /**
+     * @dataProvider provider
+     */
+    public function test(JobParameterAccessorInterface $accessor, array $expected): void
+    {
+        $reader = new ParameterAccessorReader($accessor);
+        $reader->setJobExecution(JobExecution::createRoot('123456', 'testing'));
+
+        $actual = [];
+        foreach ($reader->read() as $idx => $item) {
+            $actual[$idx] = $item;
+        }
+
+        self::assertSame($expected, $actual);
+    }
+
+    public function provider(): Generator
+    {
+        yield 'Read from preserved iterable' => [
+            new StaticValueParameterAccessor([1 => 'One', 2 => 'Two', 3 => 'Three']),
+            [1 => 'One', 2 => 'Two', 3 => 'Three']
+        ];
+
+        yield 'Read from static' => [
+            new StaticValueParameterAccessor('Not iterable and converted to array'),
+            ['Not iterable and converted to array']
+        ];
+    }
+}