def test_changing_expression():
"""Change expression and get value."""
formula = Formula("2*asin(x)", 16)
assert formula.get({"x": "1"}) == "3.1415926535897932384626433832795"
assert formula.expression == "2*asin(x)"
formula.set_expression("asin(x)")
assert formula.get({"x": "1"}) == "1.57079632679489661923132169163975"
formula.expression = "sin(x)"
assert formula.get({"x":
"1"}) == "0.8414709848078965066609974948209608755664"
def test_formula_object_copy():
"""Compare Formula objects."""
formula = Formula("2*log(1)", 99)
formula2 = formula.copy()
assert formula2 != formula
assert formula2 is not formula
assert formula2.expression == formula.expression
assert formula2.precision == formula.precision
assert formula2.get() == formula.get()
formula.expression = "1"
assert formula.get() == "1"
assert formula2.get() != formula.get()
