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()
def test_changing_precision():
"""Change precision on the fly."""
formula = Formula("2*asin(x)", 16)
assert formula.get({"x": "1"})[0:16] == "3.14159265358979"
assert formula.get({"x": "1"}, 10) == "3.141592654"
formula.precision = 24
digits = 18
format_flags = FmtFlags.fixed
assert formula.get({"x": "1"}, digits,
format_flags) == "3.141592653589793238"
formula.set_precision(240)
assert formula.precision == 256
assert (formula.get({"x": "1"})[0:256] ==
"3.141592653589793238462643383279502884197169399375105820974944"
"59230781640628620899862803482534211706798214808651328230664709"
"38446095505822317253594081284811174502841027019385211055596446"
"22948954930381964428810975665933446128475648233786783165271201"
"90914564")
