PHPUnit Assertion that asserts the response content match a previous taken snapshot

snapshot.php

<?php
/**
 * Assert the response content match a previous taken snapshot.
 * If the snapshot doesn't exists on the first run it gets
 * created and the test is marked as incomplete.
 */
private function seeSnapshot()
{
    $testName = debug_backtrace()[1]['function'];
    $filename = "snapshots/{$testName}.json";
    if (file_exists($filename)) {
        $snapshot = file_get_contents($filename);
        $this->seeJson(json_decode($snapshot, true));
    } else {
        file_put_contents($filename, $this->response->getContent());
        $this->markTestIncomplete();
    }
}