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DECNET/tests/ttp/test_rule_engine.py

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3.9 KiB
Python

"""Contract tests for :mod:`decnet.ttp.impl.rule_engine` (E.1.5).
Scoped to the contract surface: shape of :class:`CompiledRule`,
constructor signature of :class:`RuleEngine`, the empty-list /
``None`` returns from :meth:`evaluate` / :meth:`watch_store`, and the
:class:`RuleSchema` field set. Behavioral assertions from E.2.5
(malformed-YAML compile failure, multi-emit fan-out, version-collision
distinct UUIDs) are present but xfail-strict pending E.3.
"""
from __future__ import annotations
import asyncio
import inspect
import pytest
from decnet.ttp.base import TaggerEvent
from decnet.ttp.impl.rule_engine import CompiledRule, RuleEngine, RuleSchema
def _ev() -> TaggerEvent:
return TaggerEvent(
source_kind="command",
source_id="src1",
attacker_uuid="att1",
identity_uuid=None,
session_id=None,
decky_id=None,
payload={},
)
class _StubStore:
"""Minimal duck-typed RuleStore for contract-phase construction."""
def test_compiled_rule_is_namedtuple_with_documented_fields():
assert issubclass(CompiledRule, tuple)
fields = CompiledRule._fields
assert fields == (
"rule_id",
"rule_version",
"name",
"applies_to",
"match_spec",
"emits",
"evidence_fields",
"state",
)
def test_compiled_rule_is_immutable():
# NamedTuple gives us field-level immutability — the atomic-swap
# property (E.2.14b) requires that a rule in the dispatch index
# cannot be mutated in place; replacement is the only legal edit.
cr = CompiledRule(
rule_id="R0001",
rule_version=1,
name="brute",
applies_to=frozenset({"command"}),
match_spec={},
emits=(("T1110", None),),
evidence_fields=("matched_tokens",),
state=object(),
)
with pytest.raises(AttributeError):
cr.rule_id = "R9999" # type: ignore[misc]
def test_rule_engine_constructs_with_store():
eng = RuleEngine(store=_StubStore()) # type: ignore[arg-type]
# Dispatch index starts empty in the contract phase.
assert eng._by_kind == {}
def test_rule_engine_init_signature_takes_store():
sig = inspect.signature(RuleEngine.__init__)
assert list(sig.parameters)[1] == "store"
def test_evaluate_returns_empty_list_in_contract_phase():
eng = RuleEngine(store=_StubStore()) # type: ignore[arg-type]
out = asyncio.run(eng.evaluate(_ev()))
assert out == []
def test_watch_store_returns_none_and_does_not_raise():
eng = RuleEngine(store=_StubStore()) # type: ignore[arg-type]
assert asyncio.run(eng.watch_store()) is None
def test_rule_schema_has_documented_fields():
fields = RuleSchema.model_fields
must_have = {
"rule_id",
"rule_version",
"name",
"applies_to",
"match",
"emits",
"evidence_fields",
}
assert must_have <= set(fields)
def test_rule_schema_validates_minimal_yaml_shape():
rs = RuleSchema.model_validate({
"rule_id": "R0001",
"rule_version": 1,
"name": "brute force ssh",
"applies_to": ["command"],
"match": {"contains": "hydra"},
"emits": [{"technique_id": "T1110"}],
})
assert rs.rule_id == "R0001"
assert rs.evidence_fields == [] # default
# ── E.2.5 deferred behavioral assertions ───────────────────────────
@pytest.mark.xfail(strict=True, reason="impl phase E.3 — malformed YAML")
def test_e25_malformed_yaml_fails_at_compile_not_evaluate():
raise AssertionError("not yet implemented")
@pytest.mark.xfail(strict=True, reason="impl phase E.3 — multi-emit fan-out")
def test_e25_one_rule_multiple_emits_produces_multiple_tags():
raise AssertionError("not yet implemented")
@pytest.mark.xfail(strict=True, reason="impl phase E.3 — rule_version collision")
def test_e25_rule_version_collision_yields_distinct_tag_uuids():
raise AssertionError("not yet implemented")