def test_lifo():
stack = Stack()
stack.push(5)
stack.push(6)
assert stack.pop() == 6
assert stack.pop() == 5
def stack_reverse(l):
s = Stack(len(l))
for e in l:
s.push(e)
r = []
while not s.is_empty():
r.append(s.pop())
return r
def test_push_pop_empty():
stack = Stack()
assert stack.empty()
stack.push(5)
assert stack.pop() == 5
assert stack.empty()
def test_capacity():
# Create a stack that can hold a single element only.
stack = Stack(1)
assert stack.empty()
stack.push(5)
# Attempting to push an additional item should fail.
with pytest.raises(TypeError) as e_info:
stack.push(6)
def stack_reverse(l):
s = Stack(len(l))
for e in l:
s.push(e)
r = []
while not s.is_empty():
r.append(s.pop())
return r
class StackPushTestCase(unittest.TestCase):
def setUp(self):
self.stack = Stack()
def test_push_should_add_item_to_the_end_of_items_list(self):
self.stack.push(1)
self.assertEqual(self.stack.items[0], 1)
self.stack.push(2)
self.assertEqual(self.stack.items[1], 2)
def test_push_should_increment_stack_size(self):
self.stack.push(1)
self.assertEqual(self.stack.size(), 1)
#-----------------------------------------------------------------------
# evaluate.py
#-----------------------------------------------------------------------
import stdio
import math
from arraystack import Stack
#-----------------------------------------------------------------------
# Read a fully parenthesized numeric expression from standard input,
# evaluate it, and write the resulting number to standard output.
ops = Stack()
values = Stack()
while not stdio.isEmpty():
token = stdio.readString()
if token == '+': ops.push(token)
elif token == '-': ops.push(token)
elif token == '*': ops.push(token)
elif token == 'sqrt': ops.push(token)
elif token == ')':
# Pop, evaluate, and push result.
op = ops.pop()
value = values.pop()
if op == '+': value = values.pop() + value
elif op == '-': value = values.pop() - value
elif op == '*': value = values.pop() * value
elif op == 'sqrt': value = math.sqrt(value)
values.push(value)
def setUp(self):
self.stack = Stack()
class StackSizeTestCase(unittest.TestCase):
def setUp(self):
self.stack = Stack()
def test_size_should_return_the_number_of_items_in_the_stack(self):
self.assertEqual(self.stack.size(), 0)
self.stack.push(1)
self.assertEqual(self.stack.size(), 1)
self.stack.push(2)
self.assertEqual(self.stack.size(), 2)
self.stack.pop()
self.assertEqual(self.stack.size(), 1)
self.stack.peek()
self.assertEqual(self.stack.size(), 1)
def setUp(self):
self.stack = Stack()
self.stack.push(1)
self.stack.push(2)
self.stack.push(3)
class StackPeekTestCase(unittest.TestCase):
def setUp(self):
self.stack = Stack()
self.stack.push(1)
self.stack.push(2)
self.stack.push(3)
def test_peek_should_return_the_last_item_of_its_items_list(self):
self.assertEqual(self.stack.peek(), 3)
self.assertEqual(self.stack.peek(), 3)
self.assertEqual(self.stack.peek(), 3)
def test_peek_should_return_none_if_stack_is_already_empty(self):
self.stack.pop()
self.stack.pop()
self.stack.pop()
self.assertEqual(self.stack.peek(), None)
def test_peek_should_not_decrement_stack_size(self):
self.stack.peek()
self.assertEqual(self.stack.size(), 3)
def test_pop():
stack = Stack()
with pytest.raises(TypeError) as e_info:
stack.pop()