def test_peek(self):
"""
Test for peek method
"""
stack = Stack()
self.assertEqual(stack.peek(), None)
stack.push(1)
stack.push(2)
stack.push(3)
self.assertEqual(stack.peek(), 3)
self.assertEqual(stack.size(), 3)
class TestStack(unittest.TestCase):
def setUp(self):
self.stack = Stack()
def test_define_a_stack(self):
self.assertIsInstance(self.stack, Stack)
def test_if_stack_is_empty(self):
self.assertTrue(self.stack.is_empty())
def test_if_stack_is_not_empty(self):
self.stack.push(1)
self.assertFalse(self.stack.is_empty())
def test_add_element_to_stack(self):
self.stack.push(1)
self.assertEquals(self.stack.stack, [1])
def test_add_element_to_an_fulfilled_stack(self):
self.stack.push(1)
with self.assertRaises(FullStackError):
self.stack.push(2)
def test_pop_an_element_to_stack(self):
self.stack.push(1)
element = self.stack.pop()
self.assertEquals(element, 1)
def test_pop_an_element_from_empty_stack(self):
with self.assertRaises(EmptyStackError):
self.stack.pop()
def test_peek_an_element_from_stack(self):
self.stack.max_size = 2 # Patch object's capacity
self.stack.push(1)
self.stack.push(2)
element = self.stack.peek()
self.assertEquals(element, 2)
def test_peek_an_element_from_empty_stack(self):
with self.assertRaises(EmptyStackError):
self.stack.peek()
def test_get_size_if_stack(self):
self.stack.push(1)
self.assertEquals(self.stack.size(), 1)
def is_balanced(string):
stack = Stack("Brackets")
for ch in string:
if ch in ["(", "{", "["]:
stack.push(ch)
else:
if ch == ")" and not stack.empty() and stack.peek() == "(":
stack.pop()
if ch == "}" and not stack.empty() and stack.peek() == "{":
stack.pop()
if ch == "]" and not stack.empty() and stack.peek() == "[":
stack.pop()
return False if stack else True