def test_stack_is_empty_empty():
"""
Test a given empty stack if it's empty.
"""
s = stack.Stack()
solution = True
assert s.is_empty() == solution
def test_stack_peek_empty():
"""
Create an empty stack, tries to take the most recent element and
compares it to the expected result.
"""
s = stack.Stack()
solution = None
assert s.peek() == solution
def evaluate(self, x=None):
if self._tokens.is_empty():
self._tokens = stack.Stack().create_from_list(tokenize.tokenize(self._func))
self._operators = stack.Stack()
self._arguments = stack.Stack()
while not self._tokens.is_empty():
next_operator = self._tokens.peek()
self._tokens.pop()
if next_operator in self.CONSTANTS:
self._arguments.push(self._get_constant(next_operator))
continue
if is_number(next_operator):
number = convert_to_number(next_operator)
self._arguments.push(number)
continue
if next_operator == "x":
if x is not None:
self._arguments.push(x)
else:
self._arguments.push(self._x)
continue
if self._operators.is_empty() or next_operator == "(":
self._operators.push(next_operator)
continue
top_operator = self._operators.peek()
if top_operator == "(" and next_operator == ")":
self._operators.pop()
elif next_operator == ")" or self._eval_before(top_operator, next_operator):
self._pop_and_evaluate()
self._tokens.push(next_operator)
else:
self._operators.push(next_operator)
while not self._operators.is_empty():
self._pop_and_evaluate()
return self._arguments.peek()
def test_stack_from_list():
"""
Create a stack from a list and compares it to the expected result.
"""
elements = [42, "23", False, "Penguin"]
solution = ["Penguin", False, "23", 42]
s = stack.Stack().create_from_list(elements)
assert s.stack == solution
def test_stack_is_empty_non_empty():
"""
Test a given non-empty stack if it's empty.
"""
s = stack.Stack()
solution = False
s.push("Hello World")
assert s.is_empty() == solution
def test_stack_pop_empty():
"""
Try to pop the most recently added element from an empty stack.
"""
s = stack.Stack()
try:
s.pop()
except IndexError:
fail("An IndexError was raised, which should never happen.")
def test_stack_from_empty_list():
"""
Create a stack from an empty list and compares it to the expected
result.
"""
elements = []
solution = []
s = stack.Stack().create_from_list(elements)
assert s.stack == solution
def test_stack_push():
"""
Create an empty stack, pushes elements to it and compares the
expected result with the actual property.
"""
s = stack.Stack()
solution = ["Hello", "World", 42]
s.push("Hello")
s.push("World")
s.push(42)
assert s.stack == solution
def test_stack_pop_non_empty():
"""
Create an empty stack, pushes elements to it, removes elements and
compares the expected result with the actual property.
"""
s = stack.Stack()
solution = [True, "World", 42]
s.push(True)
s.push("World")
s.push(42)
s.push(13.0)
s.pop()
assert s.stack == solution
def test_stack_peek_non_empty():
"""
Create an empty stack, pushes elements to it, removes elements and
takes the most recently added element to compare it to the expected
result.
"""
s = stack.Stack()
solution = 42
s.push(True)
s.push("World")
s.push(42)
s.push(13.0)
s.pop()
assert s.peek() == solution
def __init__(self, func: str, x=None):
self._func = func
self._tokens = stack.Stack().create_from_list(tokenize.tokenize(func))
self._operators = stack.Stack()
self._arguments = stack.Stack()
self._x = convert_to_number(x) if isinstance(x, str) else x