def test_stack_pop(self):
t = Transition(fr='start', to='end', match='test', pop=True)
state = 'start'
stack = [('x', 'value')]
token = 'test'
t.apply(state, stack, token)
assert len(stack) == 0
def test_stack_push(self):
t = Transition(fr='start', to='end', match='test', param='t')
state = 'start'
stack = []
token = 'test'
t.apply(state, stack, token)
assert len(stack) == 1 and stack[0] == ('t', 'test')
def test_matching_transition_applied(self):
t = Transition(fr='start', to='end', match='test')
state = 'start'
stack = []
token = 'test'
assert t.apply(state, stack, token) == 'end'
def test_match_on_stack_required(self):
t = Transition(fr='start', to='end', match='test', stack_match='t')
state = 'start'
stack = [('x', 'value')]
token = 'test'
assert t.apply(state, stack, token) is None
def test_matching_on_both_input_and_stack(self):
t = Transition(fr='start', to='end', match='test', stack_match='t')
state = 'start'
stack = [('t', 'value')]
token = 'test'
assert t.apply(state, stack, token) == 'end'
def test_ignored_if_no_match(self):
t = Transition(fr='start', to='end', match='testing')
state = 'start'
stack = []
token = 'test'
assert t.apply(state, stack, token) is None
def test_pop_before_push(self):
t = Transition(fr='start', to='end', match='test', pop=True, param='t')
state = 'start'
stack = [('x', 'value')]
token = 'test'
assert t.apply(state, stack, token) == 'end'
assert len(stack) == 1 and stack[0] == ('t', 'test')
def test_pop_ignored_if_stack_empty(self):
t = Transition(fr='start', to='end', match='test', pop=True)
state = 'start'
stack = []
token = 'test'
assert t.apply(state, stack, token) is None
assert len(stack) == 0