PHPUnit – catch message from Throwable class

In my Symfony project, I am writing tests. I wrote all tests that are covering my CustomException. But, I want to write separate test to catch the one with Throwable. But, as all my cases are covered with CustomException, I do not know the way how to write a tests that will catch the message in Throwable.

From Controller:

 /**
 * @Route("/endpoint", methods={"POST"}, name="endpoint_name")
 */
public function someMethod($uuid)
 try {
        $this->myService->someServiceMethod($id);
        return $this->success("SUCCESS");
    } catch (CustomException $e) {
        return $this->handleCustomException($e);
    } catch (Throwable $e) {
        $this->logger->error("FAILED: " . $e->getMessage(), [
            $id
        ]);
        return $this->error("FAILED");
    }

Any thoughts?

public function testSomeMethod(): void
{
    $this->client->request(
        Request::METHOD_POST,
        self::API_URL . self::POST_ENDPOINT,
        [],
        [],
        [
            'CONTENT_TYPE' => 'application/json',
            'ACCEPT' => 'application/json',
        ]
    );

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

    $this->assertContains('Some message from Custom Exception!', $responseBody['error']);
    $this->assertEquals(405, $response->getStatusCode());
}

This is the test for my Custom Exception that is working.
Is there any way I can wrote the same test but to catch the message from Throwable class.