tests/test_fusion.py

import sys; sys.path.insert(0, "src")
from buddy_fusion.fusion import Lineage, Creature
from buddy_fusion.fallback import fallback_genome


def test_add_ancestor_has_no_parents_and_gen_0():
    lin = Lineage()
    c = lin.add(fallback_genome(1))
    assert c.generation == 0 and c.parent_ids == ()


def test_fuse_creates_gen_1_child_with_two_parents():
    lin = Lineage()
    a = lin.add(fallback_genome(1)); b = lin.add(fallback_genome(2))
    child = lin.fuse(a.id, b.id, seed=9)  # uses deterministic fallback when no runtime
    assert child.generation == 1
    assert set(child.parent_ids) == {a.id, b.id}
    assert lin.get(child.id) is child


def test_generation_increments_from_max_parent():
    lin = Lineage()
    a = lin.add(fallback_genome(1)); b = lin.add(fallback_genome(2))
    c1 = lin.fuse(a.id, b.id, seed=1)
    c2 = lin.fuse(c1.id, a.id, seed=2)
    assert c2.generation == 2


def test_serialize_roundtrip():
    lin = Lineage()
    a = lin.add(fallback_genome(1)); b = lin.add(fallback_genome(2))
    lin.fuse(a.id, b.id, seed=3)
    restored = Lineage.from_dict(lin.to_dict())
    assert len(restored.creatures) == 3


def test_bloodline_of_fresh_hatch_is_parents_then_child():
    lin = Lineage()
    a = lin.add(fallback_genome(1)); b = lin.add(fallback_genome(2))
    child = lin.fuse(a.id, b.id, seed=3)
    chain = lin.bloodline(child.id)
    assert [c.id for c in chain] == [a.id, b.id, child.id]  # oldest-first, both parents
    assert chain[-1] is child


def test_bloodline_includes_descendants_when_present():
    lin = Lineage()
    a = lin.add(fallback_genome(1)); b = lin.add(fallback_genome(2))
    c1 = lin.fuse(a.id, b.id, seed=1)          # gen 1
    grandchild = lin.fuse(c1.id, a.id, seed=2)  # gen 2, child of c1
    chain = lin.bloodline(c1.id)
    ids = [c.id for c in chain]
    assert c1.id in ids and grandchild.id in ids  # spine pulls in the descendant
    assert ids == sorted(ids, key=lambda x: chain[ids.index(x)].generation)  # generation-ordered


def test_bloodline_unknown_id_is_empty():
    lin = Lineage()
    assert lin.bloodline("nope") == []


def test_bloodline_is_bounded_on_deep_tree():
    lin = Lineage()
    a = lin.add(fallback_genome(1)); b = lin.add(fallback_genome(2))
    focus = lin.fuse(a.id, b.id, seed=0)
    for i in range(8):  # long descendant chain
        focus = lin.fuse(focus.id, a.id, seed=i + 10)
    # focus is the deepest node; ancestry up is capped, so the chain never explodes
    assert len(lin.bloodline(a.id)) <= 8