import sys
import os
import pytest

# Ensure the src layout is on PYTHONPATH for tests without installing the package
ROOT = os.path.abspath(os.path.join(os.path.dirname(__file__), ".."))
SRC = os.path.join(ROOT, "src")
if SRC not in sys.path:
    sys.path.insert(0, SRC)

from idea34_openpassmarket_privacy_preserving.core import LocalProblem, PerformanceSignal, PrivacyBudget, aggregate_signals


def test_privacy_budget_consume():
    budget = PrivacyBudget(budget=5.0, leakage_model="Laplace")
    assert budget.consume(2.0) is True
    assert budget.used == 2.0
    # Exceeding budget should fail gracefully
    assert budget.consume(4.0) is False
    assert budget.used == 2.0


def test_aggregate_signals_basic():
    s1 = PerformanceSignal(metric="runtime_ms", value=120.0, unit="ms", privacy_tag="v1", version=1)
    s2 = PerformanceSignal(metric="runtime_ms", value=110.0, unit="ms", privacy_tag="v1", version=1)
    budget = PrivacyBudget(budget=10.0, leakage_model="Laplace")
    merged = aggregate_signals([s1, s2], budget)
    assert merged.metric == "aggregate_runtime_ms" or merged.metric == "aggregate_runtime"
    assert merged.value == pytest.approx((120.0 + 110.0) / 2.0)