from datetime import UTC, datetime, timedelta
import unittest

from production_analytics.domain import SourceRange


class SourceRangeTests(unittest.TestCase):
    def test_accepts_ordered_timestamps(self) -> None:
        start = datetime(2026, 1, 1, tzinfo=UTC)
        source_range = SourceRange(start=start, end=start + timedelta(minutes=1))

        self.assertEqual(source_range.start, start)


    def test_rejects_reverse_interval(self) -> None:
        end = datetime(2026, 1, 1, tzinfo=UTC)

        with self.assertRaisesRegex(ValueError, "must not precede"):
            SourceRange(start=end + timedelta(seconds=1), end=end)