"""The retired numerical backend must not become a hidden runtime dependency."""
import os
from pathlib import Path
import subprocess
import sys
import unittest
from unittest.mock import patch

from app.simulation.backends import numeric_engine_name


class NativeOnlyBackendTests(unittest.TestCase):
    def test_python_backend_is_rejected_explicitly(self):
        with patch.dict(os.environ, {'SIMULATION_NUMERIC_ENGINE': 'python'}):
            with self.assertRaisesRegex(ValueError, 'removed'):
                numeric_engine_name()
        self.assertEqual(numeric_engine_name('native-c'), 'native')

    def test_api_and_compiler_import_without_numpy_or_scipy(self):
        code = '''
import importlib.abc
import sys
from pathlib import Path
class NoNumericalPython(importlib.abc.MetaPathFinder):
    def find_spec(self, fullname, path=None, target=None):
        if fullname.split('.')[0] in ('numpy', 'scipy'):
            raise AssertionError('Retired numerical dependency imported: '+fullname)
sys.meta_path.insert(0, NoNumericalPython())
from app.main import compile_system_xml_network
from app.simulation.native_codegen.compiler import compile_native_program
from app.system_xml import validate_system_xml_document
doc = validate_system_xml_document(Path('tests/data/native-skill-test.xml').read_bytes()).document
program = compile_native_program(compile_system_xml_network(doc))
assert len(program.state_keys) == 12
assert len(program.variables) == 175
assert not any(name.startswith('app.simulation.solvers.') for name in sys.modules)
'''
        subprocess.run([sys.executable, '-c', code], cwd=Path(__file__).resolve().parents[1],
                       capture_output=True, text=True, check=True, timeout=30)