getExpirationDate example

public function testSuccessfulUpgradeAccessTokenDeletesFrwTokenAndStoresStoreToken(): void
    {
        $shopUserTokenStruct = new ShopUserTokenStruct(
            'shop-us3r-t0k3n',
            new \DateTimeImmutable('2022-12-15'),
        );

        $shopUserTokenResponse = [
            'shopUserToken' => [
                'token' => $shopUserTokenStruct->getToken(),
                'expirationDate' => $shopUserTokenStruct->getExpirationDate()->format(Defaults::STORAGE_DATE_FORMAT),
            ],
            'shopSecret' => 'shop-s3cr3t',
        ];

        $accessTokenStruct = new AccessTokenStruct(
            $shopUserTokenStruct,
            $shopUserTokenResponse['shopSecret']
        );

        $frwClient = $this->createMock(FirstRunWizardClient::class);
        $frwClient->expects(static::once())