def test_pop_non_empty_stack(self):
stack = StackArray([4, 9])
value = stack.pop()
self.assertEqual('4', str(stack))
self.assertEqual('9', str(value))
def test_push_pop_from_empty_to_empty_stack(self):
stack = StackArray()
stack.push(1)
stack.pop()
stack.push(1)
stack.push(2)
stack.push(3)
stack.push(4)
stack.push(5)
stack.push(6)
stack.push(7)
stack.push(8)
stack.push(9)
self.assertEqual('1, 2, 3, 4, 5, 6, 7, 8, 9', str(stack))
stack.pop()
stack.push(9)
stack.pop()
stack.pop()
stack.pop()
stack.pop()
stack.pop()
stack.pop()
stack.pop()
stack.pop()
stack.pop()
self.assertEqual('', str(stack))
def test_pop_on_empty_stack(self):
stack = StackArray()
with self.assertRaises(ValueError):
stack.pop()
self.assertEqual('', str(stack))