import unittest
from importlib.util import spec_from_file_location, module_from_spec
from pathlib import Path
spec = spec_from_file_location('baseline_math', Path(__file__).with_name('baseline-math.py'))
module = module_from_spec(spec); spec.loader.exec_module(module)


class BaselineMathTests(unittest.TestCase):
    def test_metric_offset_is_not_a_baseline_shift(self):
        result = module.compare(56, 92, 92, 67, 100/3, -250)
        self.assertGreater(result['oldCellDeltaMm'], 2)
        self.assertEqual(result['baselineDeltaMm'], 0)
        self.assertAlmostEqual(result['cellFormulaResidualPx'], 0)

    def test_actual_render_shift_still_exceeds_same_two_mm_bound(self):
        result = module.compare(56, 92, 112, 87, 100/3, -250)
        self.assertGreater(result['baselineDeltaMm'], 2)

    def test_descriptor_sign_is_normalised_like_installed_pdfminer(self):
        self.assertEqual(module.compare(56,92,92,67,100/3,250), module.compare(56,92,92,67,100/3,-250))

    def test_wrong_font_cell_metadata_is_detected(self):
        self.assertGreater(module.compare(56,92,92,60,100/3,-250)['cellFormulaResidualPx'], 1)

    def test_exact_physical_unit_conversion(self):
        self.assertAlmostEqual(module.MM_PER_PIXEL * 96, 25.4)


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