from sympy import Symbol, binomial

from .context import _Add, _Mul, _Pow, assert_equal

x = Symbol("x", real=True)
y = Symbol("y", real=True)
theta = Symbol("theta", real=True)
gamma = Symbol("gamma", real=True)


def test_binomial_numeric():
    assert_equal("\\binom{16}{2}", binomial(16, 2))


def test_binomial_symbols():
    assert_equal("\\binom{x}{y}", binomial(x, y))


def test_binomial_greek_symbols():
    assert_equal("\\binom{\\theta}{\\gamma}", binomial(theta, gamma))


def test_binomial_expr():
    assert_equal(
        "\\binom{16+2}{\\frac{4}{2}}",
        binomial(_Add(16, 2), _Mul(4, _Pow(2, -1)), evaluate=False),
    )


def test_choose_numeric():
    assert_equal("\\choose{16}{2}", binomial(16, 2))


def test_choose_symbols():
    assert_equal("\\choose{x}{y}", binomial(x, y))


def test_choose_greek_symbols():
    assert_equal("\\choose{\\theta}{\\gamma}", binomial(theta, gamma))
