def __call__(self, attrs):
"""Performs validation (called by DRF)."""
errors = {}
for field in self.fields:
if self.instance and is_blank(getattr(self.instance, field)):
continue
if self.partial and field not in attrs:
continue
if is_blank(attrs.get(field)):
errors[field] = self.required_message
if errors:
raise serializers.ValidationError(errors)
def __call__(self, combiner) -> bool:
"""Test whether all of the fields are blank."""
return all(is_blank(combiner[field]) for field in self._fields)
def test_is_blank(value, blank):
"""Tests is_blank() for various values."""
assert is_blank(value) == blank