PHPUnit – test expected amount of items and check values

I am writing tests in PHP unit and as assertArraySubset() is deprecated I want to check that expected properties are sent and not more than the expected ones. Which I did:

    public function testPost(): void
    {
    $this->client->request(
        Request::METHOD_GET,
        self::ENDPOINT
        ),
        [],
        [],
        [
            'CONTENT_TYPE' => 'application/json',
        ]
    );

    $response = $this->client->getResponse();
    $responseBody = json_decode($response->getContent(), true);

    // compare structure (keys)
    $this->assertTrue(
        empty(array_diff_key($this->expected, $responseBody["data"][0])) &&
        empty(array_diff_key($responseBody["data"][0], $this->expected))
    );
}

Array:

 $this->expected = array(
        "meta" => json_decode('{"author": ["123-456-7890"], "category": ["www", "abc"]}', true),
        "post" => '{}',
        "scheduledTime" => 1641834440
    );

Also I want to cover two more cases but have not find a way for it:

• That expected amount of posts are returned
• That expected post is returned and has expected values for all
  properties.