from pytest import approx, fail

from polynomial import Polynomial

def test_construct_polynomial_error():
    coe = [3.5, -4.6, 0] # 3.5 - 4.6x + 0x^2
    try:
        p = Polynomial(coe) #
    except RuntimeError as ex:
        print(ex)
        pass

def test_construct_quadratic_polynomial():
    coe = [3, -4.5, 1.5] # 3 - 4.5x + 1.5x^2
    p = Polynomial(coe)
    assert p.getExponent(0) == 3
    #e = p[0]

def test_get_coefficient():
    coe = [3, -4.5, 1.5] # 3 - 4.5x + 1.5x^2
    p = Polynomial(coe)
    for idx in range(0, len(coe)):
        assert p[idx] == coe[idx]
    
def test_get_coefficient_bad_argument():
    coe = [3, -4.5, 1.5] # 3 - 4.5x + 1.5x^2
    p = Polynomial(coe)
    try:
        p[-1]
        fail("Expected an exception")
    except IndexError as ex:
        pass


def test_eval():
    coe = [3, 2, 1] #  3 + 2x + x^2
    p = Polynomial(coe)
    w = p.eval(0) # 
    assert w == 3
    w = p.eval(1)
    assert w == 6
    w = p.eval(-1)
    
def test_eval_per_operator():
    coe = [3, 2, 1] #  3 + 2x + x^2
    p = Polynomial(coe)
    w = p(-4.5)
    assert w == approx(14.25) 

def test_eval_per_operator_with_str_argument():
    coe = [3, 2, 1] #  3 + 2x + x^2
    p = Polynomial(coe)
    try:
        w = p("hello world")
        fail("Bad argument")
    except TypeError as ex:
        #assert ex.message == "Bad argument"
        print(ex)



def test_approximate_eval():
    coe = [3, 2, 1] #  3 + 2x + x^2
    p = Polynomial(coe)
    w = p.eval(1.25)
    assert w == approx(7.0625)
    w = p.eval(1/3)
    assert w == approx(3.77777777)