test.php

<?php

foreach ($classMetadata->getEmbeddedClasses() as $embeddedMetadata) {
    if ($embeddedMetadata->isInherited()) {
        continue;
    }

    $event->getClassMetadata()->mapField([
        'fieldName'  => $embeddedMetadata->getPropertyName(),
        'columnName' => $embeddedMetadata->getColumnAttribute()->name,
        'type'       => $embeddedMetadata->getColumnAttribute()->type,
    ]);
}

// ~~~

$embeddedClasses = new Collection($classMetadata->getEmbeddedClasses());
$embeddedClasses
    ->filter(function ($embeddedMetadata) {
        return false === $embeddedMetadata->isInherited();
    })
    ->each(function ($embeddedMetadata) use ($event) {
        $event->getClassMetadata()->mapField([
            'fieldName'  => $embeddedMetadata->getPropertyName(),
            'columnName' => $embeddedMetadata->getColumnAttribute()->name,
            'type'       => $embeddedMetadata->getColumnAttribute()->type,
        ]);
    });