def test_RPN_stack_underflow():
inst = RPN()
s = "1 +"
assert inst.evaluate(s) == "Stack underflow" and inst.stack.items == []
def test_RPN_evaluate():
inst = RPN()
s = "12 7 * 18 + 47 8 / - 3 +"
assert inst.evaluate(s) == [99.125] and inst.stack.items == []
def test_RPN_evaluate():
inst = RPN()
s = "12 7 * 18 + 47 8 / - 3 +"
assert inst.evaluate(s) == [99.125] and inst.stack.items == []
def test_RPN_stack_underflow():
inst = RPN()
s = "1 +"
assert inst.evaluate(s) == "Stack underflow" and inst.stack.items == []
