#!/usr/bin/env python3
"""
Unit tests for `planet_simulation.oasis_ring_iterations` (T-964, PR #210
review — hoshe).

GRID_W is ALREADY 1024 in production (not a future value) — this pins the
`binary_dilation` iteration counts the oasis-vegetation-ring code actually
uses TODAY (4/8), not just the historical 512-baseline values (2/4) the
original authored constants were tuned at. See the module docstring on
`oasis_ring_iterations` in `planet_simulation.py` for the scaling rationale.

Pure arithmetic (no numpy/scipy dependency) — stdlib `unittest` only. Run
directly or via `make test-tooling`:
  .venv/bin/python tooling/test_planet_oasis_rings.py
"""

import sys
import unittest
from pathlib import Path

sys.path.insert(0, str(Path(__file__).resolve().parent.parent))

from tooling.domains.atlas.planet.planet_simulation import GRID_W, oasis_ring_iterations  # noqa: E402


class OasisRingScalingTests(unittest.TestCase):
    def test_historical_512_baseline_yields_authored_2_and_4(self):
        # The values the oasis-ring code was originally authored/tuned at.
        self.assertEqual(oasis_ring_iterations(512), (2, 4))

    def test_current_production_1024_doubles_to_4_and_8(self):
        # GRID_W is 1024 in production TODAY (T-964 finding, PR #210 review) —
        # this is the LIVE behavior every planet generation run exercises now,
        # not a future/hypothetical value.
        self.assertEqual(oasis_ring_iterations(1024), (4, 8))

    def test_matches_the_actual_module_global_grid_w(self):
        # Fixture sanity: whatever GRID_W the module currently declares must
        # be the value this test suite is pinning against — if GRID_W ever
        # changes again, this test (not just the two explicit-value tests
        # above) will fail, forcing the new value to be pinned deliberately.
        self.assertEqual(GRID_W, 1024)

    def test_minimum_one_iteration_guard_at_a_small_grid_width(self):
        # A degenerate small grid_w must never round down to 0 iterations
        # (binary_dilation(iterations=0) is a no-op, silently disabling the
        # vegetation ring rather than erroring).
        ring1, ring2 = oasis_ring_iterations(1)
        self.assertGreaterEqual(ring1, 1)
        self.assertGreaterEqual(ring2, 1)


if __name__ == "__main__":
    unittest.main(verbosity=2)