def test_automaton_δ(self):
# fig 5.6, pag 142
states = Automaton.from_grammar(Grammar.from_string("""
S -> a A
S -> a B
A -> b B
A -> b C
B -> c A
B -> c C
C -> a
""")).δ('S', 'a')
self.assertEqual({'A', 'B'}, states)
def test_automaton_from_ε_grammar(self):
# fig 5.14 pag 147
A = Automaton.from_grammar(Grammar.from_string("""
S -> A
S -> a B
A -> a A
A -> ε
B -> b B
B -> b
"""))
s = "Automaton(N={A, B, S, ◇}, T={a, b}, transitions=(S-ε->A, S-a->B, A-a->A, A-ε->◇, B-b->B, B-b->◇), F={◇}, q0=S)"
self.assertEqual(s, str(A))
def test_automaton_from_grammar(self):
# fig 5.6, pag 142
A = Automaton.from_grammar(Grammar.from_string("""
S -> a A
S -> a B
A -> b B
A -> b C
B -> c A
B -> c C
C -> a
"""))
s = 'Automaton(N={A, B, C, S, ◇}, T={a, b, c}, transitions=(S-a->A, S-a->B, A-b->B, A-b->C, B-c->A, B-c->C, C-a->◇), F={◇}, q0=S)'
self.assertEqual(s, str(A))
def test_automaton_from_grammar_fail2b(self):
with self.assertRaisesRegex(ValueError, 'not of the aB form'):
Automaton.from_grammar(Grammar.from_string('S -> B B'))
def test_automaton_from_grammar_fail3(self):
with self.assertRaisesRegex(ValueError, 'has more than two symbols'):
Automaton.from_grammar(Grammar.from_string('S -> a b c'))