单元测试Django模型保存函数

Question

我正在创建测试，以检查自定义的校准模型保存函数是否更新资产记录(外键)，如果它是资产的最新校准记录。在live & production中，甚至在django shell中，保存函数的执行情况与预期完全相同，但在测试过程中似乎失败了.

models.py

class Asset(models.Model):
    ...
    requires_calibration = models.BooleanField()
    passed_calibration = models.BooleanField(default=False)
    calibration_date_prev = models.DateField(null=True, blank=True)
    calibration_date_next = models.DateField(null=True, blank=True)


class CalibrationRecord(models.Model):
    calibration_record_id = models.AutoField(primary_key=True)
    asset = models.ForeignKey(
                              "myapp.Asset",
                              on_delete=models.CASCADE,
                              limit_choices_to={"requires_calibration": True}
                              )
    calibration_date = models.DateField(default=timezone.now)
    calibration_date_next = models.DateField(null=True, blank=True)
    calibration_outcome = models.CharField(max_length=10, default="Pass")

    def save(self, *args, **kwargs):

        super(CalibrationRecord, self).save(*args, **kwargs)

        # Check if this is the latest calibration record for any asset, if so update asset.calibration_dates and status
        latest_asset_calibration = CalibrationRecord.objects.filter(asset=self.asset.pk).order_by(
            "-calibration_date", "-calibration_record_id")[0]

        if self.pk == latest_asset_calibration.pk:

            Asset.objects.filter(pk=self.asset.pk).update(calibration_date_prev=self.calibration_date)

            if self.calibration_date_next:
                Asset.objects.filter(pk=self.asset.pk).update(calibration_date_next=self.calibration_date_next)
            else:
                Asset.objects.filter(pk=self.asset.pk).update(calibration_date_next=None)

            if self.calibration_outcome == "Pass":
                Asset.objects.filter(pk=self.asset.pk).update(passed_calibration=True)
            else:
                Asset.objects.filter(pk=self.asset.pk).update(passed_calibration=False)

tests_models.py示例失败测试

class CalibrationRecordTests(TestCase):
    def test_calibration_record_updates_asset_cal_date_prev(self):
        """
        All calibration records should update related Asset record's "calibration_date_prev" to calibration_date
        """
        asset1 = Asset.objects.create(asset_description="Test Asset 2", requires_calibration=True)
        self.assertIsNone(asset1.calibration_date_prev)
        cal = CalibrationRecord.objects.create(asset=asset1, calibration_description="Test Calibration 2", calibration_date=timezone.now())
        self.assertEqual(cal.calibration_date, asset1.calibration_date_prev)

错误日志

======================================================================
FAIL: test_calibration_record_updates_asset_cal_date_prev (assetregister.tests_models.CalibrationRecordTests)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "C:\[path]\app\tests_models.py", line 159, in test_calibration_record_updates_asset_cal_date_prev
self.assertEqual(cal.calibration_date, asset1.calibration_date_prev)
AssertionError: datetime.datetime(2018, 2, 26, 12, 26, 34, 457513, tzinfo=<UTC>) != None
======================================================================

我所有有关自定义校准记录保存功能的测试似乎都失败了，因为相关的资产记录在应该更新时没有更新。

有什么想法吗?为什么这在开发和生产过程中起作用，而不是在测试过程中呢？

尽管.create()方法应该在创建校准记录后自动执行.save()，但我甚至尝试在创建校准记录之后执行手动.save()，但它似乎仍然失败。

Answer 1

如果您发现自己在这里，最好用Model.refresh_from_db(using=None, fields=None)重新加载对象。见Django文档

还签出了从数据库重新加载django对象

Answer 2

解决了！

自定义保存函数正确更新数据库，但没有测试模型实例！需要刷新模型实例以获得任何更新，方法是使用类似于[model].objects.get()的内容再次调用它

例如：

    asset = Asset.objects.create(asset_description="Test Asset 2", requires_calibration=True)
    self.assertIsNone(asset.calibration_date_prev)
    CalibrationRecord.objects.create(asset=asset, calibration_description="Test Calibration 2",
                                     calibration_date=timezone.now())
    cal = CalibrationRecord.objects.get(calibration_description="Test Calibration 2")
    asset = Asset.objects.get(asset_description="Test Asset 2")
    self.assertEqual(cal.calibration_date, asset.calibration_date_prev)