val extension =
      Extension(
        // common name is not an extension.
        COMMON_NAME,
        false,
        "3006800109810109".decodeHex(),
      )
    val bytes = "300f060355040304083006800109810109".decodeHex()

    assertThat(CertificateAdapters.extension.toDer(extension))
      .isEqualTo(bytes)
    assertThat(CertificateAdapters.extension.fromDer(bytes))
      .isEqualTo(extension)
  }