import importlib.util
from pathlib import Path
import unittest

spec=importlib.util.spec_from_file_location('interval',Path(__file__).parents[1]/'platform_timing_nts_interval.py')
interval=importlib.util.module_from_spec(spec);spec.loader.exec_module(interval)


class IntervalTests(unittest.TestCase):
    def endpoint(self, boot, utc, error=3):
        return dict(observer_started_wall_ns=utc-100,
                    observation=dict(boot_id='a'*32,boottime_ns=boot,utc_ns=utc,
                         sampling_bracket_ns=1,observation_error_ns=error,collected_at_ns=boot+1,
                         assessment=dict(reference_time=str(utc/10**9))))

    def test_conservative_interval_and_ceil_never_profile(self):
        result=interval.analyze(self.endpoint(1,10**9),self.endpoint(4,10**9+5))
        self.assertEqual(result['elapsed_error_interval_ns'],[-8,4])
        self.assertEqual(result['observed_interval_envelope_ppb'],2666666667)
        self.assertIsNone(result['max_elapsed_error_ppb'])
        self.assertFalse(result['qualified'])

    def test_cross_boot_rejected(self):
        a,b=self.endpoint(1,10**9),self.endpoint(100,10**9+100)
        b['observation']['boot_id']='b'*32
        with self.assertRaises(ValueError):interval.analyze(a,b)

    def test_stale_reference_rejected(self):
        a,b=self.endpoint(1,10**9),self.endpoint(100,10**9+100)
        b['observer_started_wall_ns']=2*10**9
        with self.assertRaises(ValueError):interval.analyze(a,b)

    def test_overlapping_endpoints_rejected(self):
        with self.assertRaises(ValueError):interval.analyze(self.endpoint(1,10**9),self.endpoint(2,10**9+1))


if __name__=='__main__':unittest.main()