def test_substitute_into_formula_element(self):
e1 = FormulaElement()
self.assertEqual(
e1.substitute(lambda v: {'x': 42}.get(v.symbol, v)), e1)
def test_merge_formula_element_to_self(self):
e1 = FormulaElement()
self.assertEqual(e1 | e1, Formula({e1: 2}))
def test_add_formula_element_and_number(self):
with self.assertRaises(TypeError):
f = FormulaElement() + 42
def test_merge_formula_elements(self):
e1 = FormulaElement()
e2 = FormulaElement()
self.assertEqual(e1 | e2, Formula({e1: 1, e2: 1}))
def test_substitute_into_formula_element(self):
e1 = FormulaElement()
self.assertEqual(
e1.substitute(lambda v: {'x': 42}.get(v.symbol, v)), e1)
