Question

我的pytest单元测试不断返回错误ModuleNotFoundError: No module name billing。

奇怪的是，当我删除补丁语句时，可以调用计费模块中的send_invoices方法。为什么在这种情况下，mock.patch无法找到计费模块并修补该方法？

billing.py

import pdfkit
from django.template.loader import render_to_string
from django.core.mail import EmailMessage
from projectxapp.models import User

Class Billing:

  #creates a pdf of invoice. Takes an invoice dictionary
  def create_invoice_pdf(self, invoice, user_id):
    #get the html of the invoice
    file_path ='/{}-{}.pdf'.format(user_id, invoice['billing_period'])
    invoice_html = render_to_string('templates/invoice.html', invoice)
    pdf = pdfkit.from_file(invoice_html, file_path)
    return file_path, pdf

  #sends invoice to customer
  def send_invoices(self, invoices):
    for user_id, invoice in invoices.items():
            #get customers email
            email = User.objects.get(id=user_id).email
            billing_period = invoice['billing_period']
            invoice_pdf = self.create_invoice_pdf(invoice, user_id)
            email = EmailMessage(
                'Statement of credit: {}-{}'.format(user_id, billing_period),
                'Attached is your statement of credit.\
                This may also be viewed on your dashboard when you login.',
                'no-reply@trevoe.com',
                [email],
            ).attach(invoice_pdf)

            email.send(fail_silently=False)

        return True

test.py

from mock import patch
from projectxapp import billing

@pytest.mark.django_db
def test_send_invoice():
  invoices = {
    1: {
        'transaction_processing_fee': 2.00,
        'service_fee': 10.00,
        'billing_period': '2020-01-02'
    },
    2: {
        'transaction_processing_fee': 4.00,
        'service_fee': 20.00,
        'billing_period': '2020-01-02'
    }
 }

  with patch('services.billing.Billing().create_invoice_pdf') as p1:
    p1.return_value = '/invoice.pdf'
    test = billing.Billing().send_invoices(invoices)

  assert test == True

Answer 1

使用patch时，应指定模块的完整路径，包括软件包名称。另外，请勿在路径中使用括号。修改return_value对象的Mock属性，以自定义对该对象的调用的返回值：

with patch('projectxapp.billing.Billing.create_invoice_pdf') as p1:
    p1.return_value = '/invoice.pdf'
    test = billing.Billing().send_invoices(invoices)

Answer 2

解决方案

由于我已经导入了需要修补的方法的模块。我不需要使用完整路径，包括软件包名称。

已更改

patch('projectxapp.billing.Billing.create_invoice_pdf')

对此

patch('billing.Billing.create_invoice_pdf')

来自Django文档：

target应该是“ package.module.ClassName”形式的字符串。导入目标并将指定的对象替换为新对象，因此目标必须可从您从其调用patch（）的环境中导入。在执行装饰功能时（而不是在装饰时）导入目标。

尝试在方法上使用mock.patch时出现ModuleNotFoundError

2 个答案:

解决方案