The current usage of ``datetime.today()`` is at the grace of the locale settings of the test executor and the instances spun up. The ``cryptography.x509.CertificateBuilder`` ``not_valud_before`` and ``not_valid_after`` attributes do expect [0] a UTC datetime. 0: https://cryptography.io/en/latest/x509/reference/#cryptography.x509.CertificateBuilder