Django : mock (pytest) + stripe

def create_checkout_session(request, pk_reservation):
    user = request.user
    reservation = get_object_or_404(Reservation, pk=pk_reservation)
    options: ReservationOption = ReservationOption.objects.filter(reservation=reservation)
    vats: Tva = Tva.objects.all()
    reservation_verification_access(user, reservation)
    line_items = []
    tva_20 = "txr_1OeMXPJsRK4NkkZV2g1hfpHz"
    vat_dict = {vat.rate: vat.stripe_id for vat in vats}

    if not reservation.slot_in_day:
        line_items.append({
            'price_data': {
                'currency': 'eur',
                'product_data': {
                    'name': f'{reservation} sans option',
                },
                'unit_amount': reservation.total_price_night_reservation * 100,
            },
            'quantity': 1,
            'tax_rates': [tva_20],
        })
    else:
        line_items.append({
            'price_data': {
                'currency': 'eur',
                'product_data': {
                    'name': f'{reservation} sans option',
                },
                'unit_amount': reservation.get_total_price_slot_reservation * 100,
            },
            'quantity': 1,
            'tax_rates': [tva_20],
        })
    for option in options:
        tax = vat_dict.get(option.option.tva_code)
        if tax is None:
            tax = tva_20

        line_items.append({
            'price_data': {
                'currency': 'eur',
                'product_data': {
                    'name': f'{option.option.name}',
                },
                'unit_amount': option.get_price * 100,
            },
            'quantity': option.quantity,
            'tax_rates': [tax],
        })

    checkout_data = {
        "metadata": {"reservation_id": str(reservation.pk), "reservation_order": reservation.order},
        "locale": "fr",
        "line_items": line_items,
        # "automatic_tax": {'enabled': True},
        "billing_address_collection": 'required',
        "mode": 'payment',
        "invoice_creation": {"enabled": True},
        "success_url": request.build_absolute_uri(
            reverse("spa:checkout-success", kwargs={"pk_reservation": reservation.pk})),
        "cancel_url": request.build_absolute_uri(
            reverse("spa:checkout-cancel", kwargs={"pk_reservation": reservation.pk}))
    }
    if user.stripe_id:
        checkout_data["customer"] = user.stripe_id
        checkout_data["customer_update"] = {"shipping": "auto"}
    else:
        checkout_data["customer_email"] = user.email
        checkout_data["customer_creation"] = "always"
    session = stripe.checkout.Session.create(**checkout_data)

    return redirect(session.url, code=303)


def checkout_success(request, pk_reservation):
    reservation = get_object_or_404(Reservation, pk=pk_reservation)
    reservation_verification_access(request.user, reservation)
    messages.add_message(request, level=messages.INFO,
                         message=f"Votre réservation numéro {reservation.order} a bien été payée.")
    return redirect("spa:summary")


def checkout_cancel(request, pk_reservation):
    reservation = get_object_or_404(Reservation, pk=pk_reservation)
    reservation_verification_access(request.user, reservation)
    messages.add_message(request, level=messages.INFO,
                         message=f"Votre réservation numéro {reservation.order} n'a pas été payée.")
    return redirect("spa:summary")


@csrf_exempt
def stripe_webhook(request):
    # ./stripe listen --forward-to 127.0.0.1:8000/spa/stripe-webhook/
    payload = request.body
    sig_header = request.META['HTTP_STRIPE_SIGNATURE']
    endpoint_secret = settings.ENDPOINT_KEY
    event = None

    try:
        event = stripe.Webhook.construct_event(
            payload, sig_header, endpoint_secret
        )
    except ValueError as e:
        # Invalid payload
        return HttpResponse(status=400)
    except stripe.error.SignatureVerificationError as e:
        # Invalid signature
        return HttpResponse(status=400)

    if event["type"] == "checkout.session.completed":
        data = event["data"]["object"]
        user = update_user(data)
        update_reservation(data, user)

    # Passed signature verification
    return HttpResponse(status=200)