Added test cases for evaluation sub, div, mult expressions

test_calc.py

from calculator import calc, get_values_from_expr

def test_calc_add():
    result = calc("3 + 2")
    assert result == 5

def test_calc_add2():
    result = calc("300 + 20")
    assert result == 320

def test_calc_sub1():
    result = calc("5 - 3")
    assert result == 2

def test_get_values_from_expr_add():
    result = get_values_from_expr("120 + 20")
    assert result == ['120', '20']

def test_get_values_from_expr_sub():
    result = get_values_from_expr("120 - 20")
    assert result == ['120', '20']

def test_get_values_from_expr_div():
    result = get_values_from_expr("120 / 20")
    assert result == ['120', '20']

def test_get_values_from_expr_mul():
    result = get_values_from_expr("120 * 20")
    assert result == ['120', '20']