def test_print():
process("clear")
process("3")
process("4")
retv = process("print")
otherv = process("+")
assert retv == 4
assert otherv == None
assert stack == [7]
def test_plus():
process("+")
assert stack == [3]
def test_pop():
process("clear")
process("4")
process("2")
process("pop")
assert stack == [4]
def test_swap():
process("clear")
process("4")
process("2")
process("swap")
assert stack == [2, 4]
def test_clear():
process("1")
process("2")
process("clear")
assert stack == []
def test_dup():
process("clear")
process("4")
process("2")
process("dup")
assert stack == [4, 2, 2]
def test_div():
process("2")
process("/")
assert stack == [2]
def test_push():
process("1")
process("2")
assert stack == [1, 2]
def test_minus():
process("1")
process("-")
assert stack == [2]
def test_mult():
process("2")
process("*")
assert stack == [4]
def test_div2():
process("3")
process("/")
assert stack == [0]
def test_minus():
process("clear")
process("4")
process("2")
process("-")
assert stack == [2]
def test_plus():
process("clear")
process("1")
process("2")
process("+")
assert stack == [3]
def test_div2():
process("clear")
process("4")
process("2")
process("/")
assert stack == [2]
def test_mult2():
process("clear")
process("2")
process("2")
process("*")
assert stack == [4]
