def test_create_with_transitions():
q0 = State()
t1 = Transition(q0, 'c', Direction.LEFT)
t2 = Transition(q0, 'd', Direction.RIGHT)
q1 = State({'a': t1, 'b': t2})
assert q1.transitions['a'] == t1
assert q1.transitions['b'] == t2
def test_create_transition():
q0 = State()
q1 = State()
#In q0 upon reading a move to q1, output b, and move the tape 1 right
q0.create_transition('a', q1, 'b', Direction.RIGHT)
assert q0.transitions['a'].new_state == q1
assert q0.transitions['a'].output_letter == 'b'
assert q0.transitions['a'].movement_direction == Direction.RIGHT
def test_init():
s1 = State()
s2 = State()
tm = TuringMachine("ab", s1, s2, s1)
assert tm.tape == ['a', 'b', '_']
assert tm.accept_state == s1
assert tm.reject_state == s2
assert tm.current_state == s1
def test_updating():
s1 = State()
s2 = State()
t = Transition(s2, 'b', Direction.RIGHT)
s1.add_transition('a', t)
tm = TuringMachine("acd", s1, s2, s1)
assert tm.tape == ['a', 'c', 'd', '_']
tm._read('a')
assert tm.tape[0] == 'b'
assert tm.current_state == s2
def test_tape_never_negative():
s1 = State()
s2 = State()
t = Transition(s2, 'b', Direction.LEFT)
s1.add_transition('a', t)
tm = TuringMachine("acd", s1, s2, s1)
assert tm.tape == ['a', 'c', 'd', '_']
tm._read('a')
assert tm.tape[0] == 'b'
assert tm.current_state == s2
assert tm.tape_position == 0
def test_create_multiple_transitions():
q0 = State()
q1 = State()
q2 = State()
q0.create_transition('a', q1, 'b', Direction.RIGHT)
q1.create_transition('c', q2, 'd', Direction.LEFT)
with pytest.raises(KeyError):
q0.transitions['b'] is None
assert q0.transitions['a'].new_state.transitions['c'].new_state == q2
assert q1.transitions['c'].new_state == q2
assert q0.transitions['a'].new_state.transitions['c'].output_letter == 'd'
assert q1.transitions['c'].output_letter == 'd'
assert q0.transitions['a'].new_state.transitions[
'c'].movement_direction == Direction.LEFT
assert q1.transitions['c'].movement_direction == Direction.LEFT
def test_calc():
q0 = State()
t1 = Transition(q0, 'a', Direction.RIGHT)
q1 = State()
q1.add_transition('b', t1)
res = q1.calc('b')
assert res == t1
def _parse_state(dict, line):
#Match a series of valid word characters, followed by an optional space,
#and then an optional +-.
#This accepts 'q0 ' but not 'qa+'
#These are then split into two groups. The name part and the optional
#additional information
regex = re.compile('(\w*) ?([+-]?)')
res = regex.match(line)
#Add all states to the dictionary of states
#Do a small check
name = res.group(1)
assert dict != None
if name in dict:
raise InvalidInputFormat("Two or more states cannot have the same name")
dict[name] = State()
#Special test for reject state and accept state
#Additional characters will be reject by the regex so not need to test
return dict[name], res.group(2)
def test_add_transition():
q0 = State()
q1 = State()
t = Transition(q1, 'b', Direction.RIGHT)
q0.add_transition('a', t)
assert q0.transitions['a'] == t
import pytest
import sys
sys.path.append('.')
from turingmachine import Transition, Direction, State
state = State()
def test_creation():
t = Transition(state, 'a', Direction.RIGHT)
assert t.new_state == state
assert t.output_letter == 'a'
assert t.movement_direction == Direction.RIGHT
def test_malformed_creation():
with pytest.raises(ValueError):
t = Transition(None, 'a', Direction.LEFT)
with pytest.raises(ValueError):
t2 = Transition(state, None, Direction.RIGHT)
with pytest.raises(ValueError):
t3 = Transition(state, 'a', 'c')
def create_example_from_spec():
q0 = State()
q1 = State()
qa = State()
qr = State()
q0.create_transition('a', q0, 'a', Direction.RIGHT)
q0.create_transition('b', q1, 'b', Direction.RIGHT)
q0.create_transition('_', qr, '_', Direction.LEFT)
q1.create_transition('a', qr, 'a', Direction.LEFT)
q1.create_transition('b', qr, 'a', Direction.LEFT)
q1.create_transition('_', qa, 'b', Direction.LEFT)
return q0, q1, qa, qr