def METHOD_NAME(self):
    CachePackageSource.objects.update_base_source(
        package_source_id=self.cache_source.id,
        source_type=self.UPDATE_SOURCE_TYPE,
        packages=self.UPDATED_SOURCE_PACKAGES,
        **self.UPDATED_SOURCE_KWARGS
    )
    self.cache_source = CachePackageSource.objects.get(id=self.cache_source.id)
    self.assertEqual(self.cache_source.base_source.packages, self.UPDATED_SOURCE_PACKAGES)
    base_source = FileSystemSource.objects.get(id=self.cache_source.base_source_id)
    self.assertEqual(self.cache_source.base_source, base_source)