def test_key_extensibility():
"""test that you can add keys to the ask system at runtime"""
x = Symbol('x')
# make sure thie key is not defined
raises(AttributeError, "ask(x, 'my_key')")
class MyAskHandler(AskHandler):
@staticmethod
def Symbol(expr, assumptions):
return True
register_handler('my_key', MyAskHandler)
assert ask(x, 'my_key') == True
assert ask(x+1, 'my_key') == None
remove_handler('my_key', MyAskHandler)
def test_incompatible_resolutors():
x = symbols('x')
class Prime2AskHandler(AskHandler):
@staticmethod
def Number(expr, assumptions):
return True
register_handler('prime', Prime2AskHandler)
raises(ValueError, 'ask(4, Q.prime)')
remove_handler('prime', Prime2AskHandler)
class InconclusiveHandler(AskHandler):
@staticmethod
def Number(expr, assumptions):
return None
register_handler('prime', InconclusiveHandler)
assert ask(3, Q.prime) == True
