Support ignoring fields when serializing

Is your feature request related to a problem? Please describe.

When asserting on snapshots support filtering out properties that should not be matched on. This would allow deterministic snapshots when matching on objects that generate realtime values in tests without needing to mock.

Describe the solution you’d like

def test_my_dict(snapshot):
	my_dict = {
		"match_me": True,
		"do_not_match_me": time.time(),
		"nested_do_not_match": {
			"do_not_match_me": time.time(),
		},
	}
	assert my_dict == snapshot(exclude=("do_not_match_me",))

# name: test_my_dict
  <class 'dict'> {
    'match_me': True,
	'nested_do_not_match': <class 'dict'> {
	},
  }
---

Describe alternatives you’ve considered

This is already possible but is cumbersome to implement, and cannot easily be extended to other serialization types.

class OmitDataSerializer(DataSerializer):
	@classmethod
	def __filter_data(cls, data) -> Dict[str, Any]:
		return {
			key: data[key]
			for key in data
			if key not in ("do_not_match_me",)
		}
	
    @classmethod
    def serialize_dict(cls, data, **kwargs) -> str:
        return super().serialize_dict(cls.__filter_data(data), **kwargs)


class OmitDataExtension(AmberSnapshotExtension):
    def serialize(self, data):
        return OmitDataSerializer.serialize(data)


def test_my_dict(snapshot):
	my_dict = {
		"match_me": True,
		"do_not_match_me": time.time(),
		"nested_do_not_match": {
			"do_not_match_me": time.time(),
		},
	}
	assert my_dict == snapshot(extension=OmitDataExtension)

Additional context

• Supported by Jest https://jestjs.io/docs/en/snapshot-testing#property-matchers
• Much requested feature, see counterpart https://github.com/syrusakbary/snapshottest/issues/21

[taion]

That’s neat – it could definitely work for some cases (though there are a few places where we generate v5 UUIDs off other external IDs coming in). To clarify, though, we’re not blocked on this at all; we just run our custom “mask nondeterministic values” function on our data before asserting on the snapshot.

[noahnu]

Thoughts on include and exclude instead of ignore?

We could support strings (literal property matchers) and predicates