def start():
with session_scope() as session:
new_stack = Stack()
session.add(new_stack)
session.commit()
calc_id = new_stack.calc_id
return calc_id
def push(*, operand: float, id_: int) -> float:
with session_scope() as session:
stack = Stack.find_stack(id_, session)
stack.operands.append(_Operand(operand=operand))
session.commit()
return operand
def pop(*, id_: int) -> float:
with session_scope() as session:
stack = Stack.find_stack(id_, session)
# This list of operands seems to be in the right order. If it isn't then
# the query to the DB can be modified to order by the Operand stack_idx (DateTime)
# or the list can be sorted in Python.
operand = stack.operands.pop()
session.commit()
return operand.operand
def test_cascading_delete_pass():
# given
x = 1
# when
calc_id = Stack.start()
Stack.push(operand=x, id_=calc_id)
Stack.delete(id_=calc_id)
# then
stacks = Stack.stacks()
assert 0 == len(stacks)
# Check to make sure that the operands are removed through cascading delete.
with session_scope() as session:
operands = session.query(_Operand).filter(
_Operand.calc_id == calc_id).all()
assert 0 == len(operands)
def delete(*, id_: int):
with session_scope() as session:
stack = Stack.find_stack(id_, session)
if stack:
session.delete(stack)
session.commit()
def stack(*, id_: int) -> List[float]:
with session_scope() as session:
stack = Stack.find_stack(id_, session)
return [o.operand for o in stack.operands]
def stacks():
with session_scope() as session:
stacks = session.query(Stack).all()
return stacks
def peek(*, id_: int) -> float:
with session_scope() as session:
stack = Stack.find_stack(id_, session)
# Same discussion about ordering.
return stack.operands[-1].operand