def test_safe_eval(self):
data = [
('A', {'A': 1}, 1),
('A + B * C', {'A': 1, 'B': 2, 'C': 3}, 7),
('A / B * C', {'A': 1, 'B': 2, 'C': 3}, 1.5),
('A * B + C', {'A': 1, 'B': 2, 'C': 3}, 5),
('A * (B + C)', {'A': 1, 'B': 2, 'C': 3}, 5),
('A * A * 3.141592', {'A': 2}, 12.566368),
('100 / ( 1.0 - 0.5 )', None, 200.0)
]
for expr, namespace, result in data:
formula = Formula(expr)
self.assertEqual(formula.safe_eval(namespace), result)
# Test for division by zero
self.assertTrue(math.isnan(Formula('1 / 0').safe_eval()))
# Invalid expressions
with self.assertRaises(ValueError):
Formula('A + 3').safe_eval(None)
with self.assertRaises(ValueError):
Formula('B A + 3').safe_eval({'A': 1, 'B': 2})
