"""trace.py 单测（A1）。"""

from app.utils.trace import current_trace, new_trace


def test_new_trace_generates_and_binds():
    tid = new_trace()
    assert tid.startswith("trc-")
    assert len(tid) == 20  # trc- + 16 hex
    assert current_trace() == tid


def test_new_trace_accepts_external_id():
    tid = new_trace("trc-external-0001")
    assert current_trace() == "trc-external-0001"
    assert tid == "trc-external-0001"


def test_uniqueness():
    ids = {new_trace() for _ in range(100)}
    assert len(ids) == 100