test: Add test for is_canonical

from lib.parsing.parser import Parser

def is_can(dfa: str) -> bool:

    parser = Parser()

    return parser.str_to_dfa(dfa).is_canonical()

def test_can() -> None:

    assert is_can("init=1 (1,a)=1 (1,b)=2 (2,b)=1 (2,a)=1 final={2}")

    assert is_can("init=1 (1,b)=3 (1,a)=2 (2,b)=1 (2,a)=1 (3,a)=2 (3,b)=2 final={2}")

    assert not is_can("init=1 (1,b)=3 (1,c)=2 (2,b)=1 (2,a)=1 (3,a)=2 (3,b)=2 final={2}")

    assert not is_can("init=1 (1,a)=1 (1,b)=2 (2,b)=1 (2,b)=1 (unreach,a)=1 (unreach,b)=unreach final={2}")