def test_parse_side_by_side_symbols_should_raise_exception_but_not2(self):
algebra = BooleanAlgebra()
expr_str = '(a or b) c'
try:
algebra.parse(expr_str)
except ParseError as pe:
assert pe.error_code == PARSE_INVALID_EXPRESSION
def test_or(self):
algebra = BooleanAlgebra()
exp = algebra.parse("a|b|c")
for a in [True, False]:
for b in [True, False]:
for c in [True, False]:
self.assertEqual(exp(a=a, b=b, c=c), a or b or c)
def test_parse_side_by_side_symbols_with_parens_raise_exception(self):
algebra = BooleanAlgebra()
expr_str = '(a) (b)'
try:
algebra.parse(expr_str)
except ParseError as pe:
assert pe.error_code == PARSE_INVALID_NESTING
def test_parse_side_by_side_symbols_raise_exception(self):
algebra = BooleanAlgebra()
expr_str = 'a b'
try:
algebra.parse(expr_str)
except ParseError as pe:
assert pe.error_code == PARSE_INVALID_SYMBOL_SEQUENCE
def test_parse_with_mixed_operators_multilines_and_custom_symbol(self):
class MySymbol(Symbol):
pass
expr_str = '''(a or ~ b +_c ) and
d & ( ! e_
| (my * g OR 1 or 0) ) AND that '''
algebra = BooleanAlgebra(Symbol_class=MySymbol)
expr = algebra.parse(expr_str)
expected = algebra.AND(
algebra.OR(
algebra.Symbol('a'),
algebra.NOT(algebra.Symbol('b')),
algebra.Symbol('_c'),
),
algebra.Symbol('d'),
algebra.OR(
algebra.NOT(algebra.Symbol('e_')),
algebra.OR(
algebra.AND(
algebra.Symbol('my'),
algebra.Symbol('g'),
),
algebra.TRUE,
algebra.FALSE,
),
),
algebra.Symbol('that'),
)
self.assertEqual(expected.pretty(), expr.pretty())
self.assertEqual(expected, expr)
def test_simplify_complex_expression_parsed_with_simplify(self):
# FIXME: THIS SHOULD NOT FAIL
algebra = BooleanAlgebra()
a = algebra.Symbol('a')
b = algebra.Symbol('b')
c = algebra.Symbol('c')
d = algebra.Symbol('d')
test_expression_str = '''
(~a&~b&~c&~d) | (~a&~b&~c&d) | (~a&b&~c&~d) |
(~a&b&c&d) | (~a&b&~c&d) | (~a&b&c&~d) |
(a&~b&~c&d) | (~a&b&c&d) | (a&~b&c&d) | (a&b&c&d)
'''
parsed = algebra.parse(test_expression_str, simplify=True)
test_expression = ((~a & ~b & ~c & ~d) | (~a & ~b & ~c & d) |
(~a & b & ~c & ~d) | (~a & b & c & d) |
(~a & b & ~c & d) | (~a & b & c & ~d) |
(a & ~b & ~c & d) | (~a & b & c & d) |
(a & ~b & c & d) | (a & b & c & d)).simplify()
# we have a different simplify behavior for expressions built from python expressions
# vs. expression built from an object tree vs. expression built from a parse
self.assertEqual(parsed.pretty(), test_expression.pretty())
def test_demorgan(self):
algebra = BooleanAlgebra()
a = algebra.Symbol('a')
b = algebra.Symbol('b')
self.assertEqual(algebra.parse('~(a&b)').demorgan(), ~a | ~b)
self.assertEqual(algebra.parse('~(a|b|c)').demorgan(), algebra.parse('~a&~b&~c'))
self.assertEqual(algebra.parse('~(~a&b)').demorgan(), a | ~b)
def test_cancel(self):
algebra = BooleanAlgebra()
a = algebra.Symbol('a')
self.assertEqual(~a, (~a).cancel())
self.assertEqual(a, algebra.parse('~~a').cancel())
self.assertEqual(~a, algebra.parse('~~~a').cancel())
self.assertEqual(a, algebra.parse('~~~~a').cancel())
def test_dual(self):
algebra = BooleanAlgebra()
self.assertEqual(algebra.AND(algebra.Symbol('a'), algebra.Symbol('b')).dual, algebra.OR)
self.assertEqual(algebra.OR(algebra.Symbol('a'), algebra.Symbol('b')).dual, algebra.AND)
self.assertEqual(algebra.parse('a|b').dual, algebra.AND)
self.assertEqual(algebra.parse('a&b').dual, algebra.OR)
def test_simplify_complex_expression_parsed_with_simplify(self):
# FIXME: THIS SHOULD NOT FAIL
algebra = BooleanAlgebra()
a = algebra.Symbol('a')
b = algebra.Symbol('b')
c = algebra.Symbol('c')
d = algebra.Symbol('d')
test_expression_str = '''
(~a&~b&~c&~d) | (~a&~b&~c&d) | (~a&b&~c&~d) |
(~a&b&c&d) | (~a&b&~c&d) | (~a&b&c&~d) |
(a&~b&~c&d) | (~a&b&c&d) | (a&~b&c&d) | (a&b&c&d)
'''
parsed = algebra.parse(test_expression_str, simplify=True)
test_expression = (
(~a & ~b & ~c & ~d) | (~a & ~b & ~c & d) | (~a & b & ~c & ~d) |
(~a & b & c & d) | (~a & b & ~c & d) | (~a & b & c & ~d) |
(a & ~b & ~c & d) | (~a & b & c & d) | (a & ~b & c & d) | (a & b & c & d)
).simplify()
# we have a different simplify behavior for expressions built from python expressions
# vs. expression built from an object tree vs. expression built from a parse
self.assertEqual(parsed.pretty(), test_expression.pretty())
def test_and(self):
algebra = BooleanAlgebra()
exp = algebra.parse("a&b&c")
for a in [True, False]:
for b in [True, False]:
for c in [True, False]:
self.assertEqual(exp(a=a, b=b, c=c), a and b and c)
def test_parse_invalid_nested_and_should_raise_a_proper_exception(self):
algebra = BooleanAlgebra()
expr = '''a (and b)'''
try:
algebra.parse(expr)
except ParseError as pe:
assert pe.error_code == PARSE_INVALID_NESTING
def test_subs_default(self):
algebra = BooleanAlgebra()
a, b, c = algebra.Symbol('a'), algebra.Symbol('b'), algebra.Symbol('c')
expr = a & b | c
self.assertEqual(expr.subs({}, default=algebra.TRUE).simplify(), algebra.TRUE)
self.assertEqual(expr.subs({a: algebra.FALSE, c: algebra.FALSE}, default=algebra.TRUE).simplify(), algebra.FALSE)
self.assertEqual(algebra.TRUE.subs({}, default=algebra.FALSE).simplify(), algebra.TRUE)
self.assertEqual(algebra.FALSE.subs({}, default=algebra.TRUE).simplify(), algebra.FALSE)
def test_printing(self):
algebra = BooleanAlgebra()
a = algebra.Symbol('a')
self.assertEqual(str(~a), '~a')
self.assertEqual(repr(~a), "NOT(Symbol('a'))")
expr = algebra.parse('~(a&a)')
self.assertEqual(str(expr), '~(a&a)')
self.assertEqual(repr(expr), "NOT(AND(Symbol('a'), Symbol('a')))")
def test_composite(self):
algebra = BooleanAlgebra()
exp = algebra.parse("!(a|b&(a|!c))")
for a in [True, False]:
for b in [True, False]:
for c in [True, False]:
self.assertEqual(exp(a=a, b=b, c=c),
not (a or b and (a or not c)))
def test_parse_raise_ParseError9(self):
algebra = BooleanAlgebra()
expr = '+ l-a'
try:
algebra.parse(expr)
self.fail("Exception should be raised when parsing '%s'" % expr)
except ParseError as pe:
assert pe.error_code == PARSE_INVALID_OPERATOR_SEQUENCE
def test_parse_raise_ParseError7(self):
algebra = BooleanAlgebra()
expr = 'l-a AND'
try:
algebra.parse(expr)
self.fail("Exception should be raised when parsing '%s'" % expr)
except ParseError as pe:
assert pe.error_code == PARSE_UNKNOWN_TOKEN
def test_order(self):
algebra = BooleanAlgebra()
x = algebra.Symbol(1)
y = algebra.Symbol(2)
self.assertTrue(x < ~x)
self.assertTrue(~x > x)
self.assertTrue(~x < y)
self.assertTrue(y > ~x)
def test_printing(self):
algebra = BooleanAlgebra()
a = algebra.Symbol('a')
self.assertEqual(str(~a), '~a')
self.assertEqual(repr(~a), "NOT(Symbol('a'))")
expr = algebra.parse('~(a&a)')
self.assertEqual(str(expr), '~(a&a)')
self.assertEqual(repr(expr), "NOT(AND(Symbol('a'), Symbol('a')))")
def test_subs(self):
algebra = BooleanAlgebra()
a, b, c = algebra.Symbol('a'), algebra.Symbol('b'), algebra.Symbol('c')
expr = a & b | c
self.assertEqual(expr.subs({a: b}).simplify(), b | c)
self.assertEqual(expr.subs({a: a}).simplify(), expr)
self.assertEqual(expr.subs({a: b | c}).simplify(), algebra.parse('(b|c)&b|c').simplify())
self.assertEqual(expr.subs({a & b: a}).simplify(), a | c)
self.assertEqual(expr.subs({c: algebra.TRUE}).simplify(), algebra.TRUE)
def test_get_symbols_return_all_symbols_in_original_order(self):
alg = BooleanAlgebra()
exp = alg.parse('a and b or True and a and c')
assert [
alg.Symbol('a'),
alg.Symbol('b'),
alg.Symbol('a'),
alg.Symbol('c')
] == exp.get_symbols()
def test_parse_invalid_nested_and_should_raise_a_proper_exception(self):
algebra = BooleanAlgebra()
expr = '''a (and b)'''
with self.assertRaises(ParseError) as context:
algebra.parse(expr)
self.assertEqual(context.exception.error_code,
PARSE_INVALID_NESTING)
def test_allowing_additional_characters_in_tokens(self):
algebra = BooleanAlgebra(allowed_in_token=('.', '_', '-', '+'))
test_expr = 'l-a AND b+c'
expr = algebra.parse(test_expr)
expected = algebra.AND(
algebra.Symbol('l-a'),
algebra.Symbol('b+c')
)
self.assertEqual(expected, expr)
def test_dual(self):
algebra = BooleanAlgebra()
self.assertEqual(algebra.AND(algebra.Symbol('a'), algebra.Symbol('b')).dual, algebra.OR)
self.assertEqual(algebra.OR(algebra.Symbol('a'), algebra.Symbol('b')).dual, algebra.AND)
self.assertEqual(algebra.parse('a|b').dual, algebra.AND)
self.assertEqual(algebra.parse('a&b').dual, algebra.OR)
def test_distributive(self):
algebra = BooleanAlgebra()
a = algebra.Symbol('a')
b = algebra.Symbol('b')
c = algebra.Symbol('c')
d = algebra.Symbol('d')
e = algebra.Symbol('e')
self.assertEqual((a & (b | c)).distributive(), (a & b) | (a & c))
t1 = algebra.AND(a, (b | c), (d | e))
t2 = algebra.OR(algebra.AND(a, b, d), algebra.AND(a, b, e), algebra.AND(a, c, d), algebra.AND(a, c, e))
self.assertEqual(t1.distributive(), t2)
def test_simplify(self):
algebra = BooleanAlgebra()
a = algebra.Symbol('a')
self.assertEqual(~a, ~a)
assert algebra.Symbol('a') == algebra.Symbol('a')
self.assertNotEqual(a, algebra.parse('~~a'))
self.assertEqual(a, (~~a).simplify())
self.assertEqual(~a, (~~ ~a).simplify())
self.assertEqual(a, (~~ ~~a).simplify())
self.assertEqual((~(a & a & a)).simplify(), (~(a & a & a)).simplify())
self.assertEqual(a, algebra.parse('~~a', simplify=True))
def test_simplify(self):
algebra = BooleanAlgebra()
a = algebra.Symbol('a')
self.assertEqual(~a, ~a)
assert algebra.Symbol('a') == algebra.Symbol('a')
self.assertNotEqual(a, algebra.parse('~~a'))
self.assertEqual(a, (~~a).simplify())
self.assertEqual(~a, (~~~a).simplify())
self.assertEqual(a, (~~~~a).simplify())
self.assertEqual((~(a & a & a)).simplify(), (~(a & a & a)).simplify())
self.assertEqual(a, algebra.parse('~~a', simplify=True))
algebra2 = BooleanAlgebra()
self.assertEqual(a, algebra2.parse('~~a', simplify=True))
def test_literals(self):
algebra = BooleanAlgebra()
a = algebra.Symbol('a')
l = ~a
self.assertTrue(l.isliteral)
self.assertTrue(l in l.literals)
self.assertEqual(len(l.literals), 1)
l = algebra.parse('~(a&a)')
self.assertFalse(l.isliteral)
self.assertTrue(a in l.literals)
self.assertEqual(len(l.literals), 1)
l = algebra.parse('~(a&a)', simplify=True)
self.assertTrue(l.isliteral)
def test_literals(self):
algebra = BooleanAlgebra()
a = algebra.Symbol('a')
l = ~a
self.assertTrue(l.isliteral)
self.assertTrue(l in l.literals)
self.assertEqual(len(l.literals), 1)
l = algebra.parse('~(a&a)')
self.assertFalse(l.isliteral)
self.assertTrue(a in l.literals)
self.assertEqual(len(l.literals), 1)
l = algebra.parse('~(a&a)', simplify=True)
self.assertTrue(l.isliteral)
def test_parse_recognizes_trueish_and_falsish_symbol_tokens(self):
expr_str = 'True or False or None or 0 or 1 or TRue or FalSE or NONe'
algebra = BooleanAlgebra()
expr = algebra.parse(expr_str)
expected = algebra.OR(
algebra.TRUE,
algebra.FALSE,
algebra.FALSE,
algebra.FALSE,
algebra.TRUE,
algebra.TRUE,
algebra.FALSE,
algebra.FALSE,
)
self.assertEqual(expected, expr)
def test_bool(self):
algebra = BooleanAlgebra()
a, b, c = algebra.Symbol('a'), algebra.Symbol('b'), algebra.Symbol('c')
expr = a & b | c
self.assertRaises(TypeError, bool, expr.subs({a: algebra.TRUE}))
self.assertRaises(TypeError, bool, expr.subs({b: algebra.TRUE}))
self.assertRaises(TypeError, bool, expr.subs({c: algebra.TRUE}))
self.assertRaises(TypeError, bool, expr.subs({a: algebra.TRUE, b: algebra.TRUE}))
result = expr.subs({c: algebra.TRUE}, simplify=True)
result = result.simplify()
self.assertEqual(algebra.TRUE, result)
result = expr.subs({a: algebra.TRUE, b: algebra.TRUE}, simplify=True)
result = result.simplify()
self.assertEqual(algebra.TRUE, result)
def test_parse_recognizes_trueish_and_falsish_symbol_tokens(self):
expr_str = 'True or False or None or 0 or 1 or TRue or FalSE or NONe'
algebra = BooleanAlgebra()
expr = algebra.parse(expr_str)
expected = algebra.OR(
algebra.TRUE,
algebra.FALSE,
algebra.FALSE,
algebra.FALSE,
algebra.TRUE,
algebra.TRUE,
algebra.FALSE,
algebra.FALSE,
)
self.assertEqual(expected, expr)
def test_demorgan(self):
algebra = BooleanAlgebra()
a = algebra.Symbol('a')
b = algebra.Symbol('b')
c = algebra.Symbol('c')
self.assertEqual(algebra.parse('~(a&b)').demorgan(), ~a | ~b)
self.assertEqual(algebra.parse('~(a|b|c)').demorgan(), algebra.parse('~a&~b&~c'))
self.assertEqual(algebra.parse('~(~a&b)').demorgan(), a | ~b)
self.assertEqual((~~(a&b|c)).demorgan(), a&b|c)
self.assertEqual((~~~(a&b|c)).demorgan(), ~(a&b)&~c)
self.assertEqual(algebra.parse('~'*10 + '(a&b|c)').demorgan(), a&b|c)
self.assertEqual(algebra.parse('~'*11 + '(a&b|c)').demorgan(), (~(a&b|c)).demorgan())
def test_class_order(self):
# FIXME: this test is cryptic: what does it do?
algebra = BooleanAlgebra()
order = (
(algebra.TRUE, algebra.FALSE),
(algebra.Symbol('y'), algebra.Symbol('x')),
(algebra.parse('x&y'),),
(algebra.parse('x|y'),),
)
for i, tests in enumerate(order):
for case1 in tests:
for j in range(i + 1, len(order)):
for case2 in order[j]:
self.assertTrue(case1 < case2)
self.assertTrue(case2 > case1)
def test_class_order(self):
# FIXME: this test is cryptic: what does it do?
algebra = BooleanAlgebra()
order = (
(algebra.TRUE, algebra.FALSE),
(algebra.Symbol('y'), algebra.Symbol('x')),
(algebra.parse('x&y'), ),
(algebra.parse('x|y'), ),
)
for i, tests in enumerate(order):
for case1 in tests:
for j in range(i + 1, len(order)):
for case2 in order[j]:
self.assertTrue(case1 < case2)
self.assertTrue(case2 > case1)
def test_parse_complex_expression_should_create_same_expression_as_python(self):
algebra = BooleanAlgebra()
a, b, c = algebra.symbols(*'abc')
test_expression_str = '''(~a | ~b | ~c)'''
parsed = algebra.parse(test_expression_str)
test_expression = (~a | ~b | ~c) # & ~d
# print()
# print('parsed')
# print(parsed.pretty())
# print('python')
# print(test_expression.pretty())
# we have a different behavior for expressions built from python expressions
# vs. expression built from an object tree vs. expression built from a parse
self.assertEqual(parsed.pretty(), test_expression.pretty())
self.assertEqual(parsed, test_expression)
def test_parse_complex_expression_should_create_same_expression_as_python(self):
algebra = BooleanAlgebra()
a, b, c = algebra.symbols(*'abc')
test_expression_str = '''(~a | ~b | ~c)'''
parsed = algebra.parse(test_expression_str)
test_expression = (~a | ~b | ~c) # & ~d
# print()
# print('parsed')
# print(parsed.pretty())
# print('python')
# print(test_expression.pretty())
# we have a different behavior for expressions built from python expressions
# vs. expression built from an object tree vs. expression built from a parse
self.assertEqual(parsed.pretty(), test_expression.pretty())
self.assertEqual(parsed, test_expression)
def test_printing(self):
parse = BooleanAlgebra().parse
self.assertEqual(str(parse('a&a')), 'a&a')
self.assertEqual(repr(parse('a&a')), "AND(Symbol('a'), Symbol('a'))")
self.assertEqual(str(parse('a|a')), 'a|a')
self.assertEqual(repr(parse('a|a')), "OR(Symbol('a'), Symbol('a'))")
self.assertEqual(str(parse('(a|b)&c')), '(a|b)&c')
self.assertEqual(repr(parse('(a|b)&c')), "AND(OR(Symbol('a'), Symbol('b')), Symbol('c'))")
def test_subtract(self):
parse = BooleanAlgebra().parse
expr = parse('a&b&c')
p1 = parse('b&d')
p2 = parse('a&c')
result = parse('b')
self.assertEqual(expr.subtract(p1, simplify=True), expr)
self.assertEqual(expr.subtract(p2, simplify=True), result)
def test_simplify(self):
algebra = BooleanAlgebra()
a = algebra.Symbol('a')
b = algebra.Symbol('b')
c = algebra.Symbol('c')
_0 = algebra.FALSE
_1 = algebra.TRUE
# Idempotence
self.assertEqual(a, (a & a).simplify())
# Idempotence + Associativity
self.assertEqual(a | b, (a | (a | b)).simplify())
# Annihilation
self.assertEqual(_0, (a & _0).simplify())
self.assertEqual(_1, (a | _1).simplify())
# Identity
self.assertEqual(a, (a & _1).simplify())
self.assertEqual(a, (a | _0).simplify())
# Complementation
self.assertEqual(_0, (a & ~a).simplify())
self.assertEqual(_1, (a | ~a).simplify())
# Absorption
self.assertEqual(a, (a & (a | b)).simplify())
self.assertEqual(a, (a | (a & b)).simplify())
self.assertEqual(b & a, ((b & a) | (b & a & c)).simplify())
# Elimination
self.assertEqual(a, ((a & ~b) | (a & b)).simplify())
expected = algebra.parse('(a&b)|(b&c)|(a&c)')
result = algebra.parse('(~a&b&c) | (a&~b&c) | (a&b&~c) | (a&b&c)',
simplify=True)
self.assertEqual(expected, result)
expected = algebra.parse('b&d')
result = algebra.parse('(a&b&c&d) | (b&d)', simplify=True)
self.assertEqual(expected, result)
expected = algebra.parse('(~b&~d&a) | (~c&~d&b) | (a&c&d)',
simplify=True)
result = algebra.parse('''(~a&b&~c&~d) | (a&~b&~c&~d) | (a&~b&c&~d) |
(a&~b&c&d) | (a&b&~c&~d) | (a&b&c&d)''',
simplify=True)
self.assertEqual(expected.pretty(), result.pretty())
def test_demorgan(self):
algebra = BooleanAlgebra()
a = algebra.Symbol('a')
b = algebra.Symbol('b')
self.assertEqual(algebra.parse('~(a&b)').demorgan(), ~a | ~b)
self.assertEqual(
algebra.parse('~(a|b|c)').demorgan(), algebra.parse('~a&~b&~c'))
self.assertEqual(algebra.parse('~(~a&b)').demorgan(), a | ~b)
def test_flatten(self):
parse = BooleanAlgebra().parse
t1 = parse('a & (b&c)')
t2 = parse('a&b&c')
self.assertNotEqual(t1, t2)
self.assertEqual(t1.flatten(), t2)
t1 = parse('a | ((b&c) | (a&c)) | b')
t2 = parse('a | (b&c) | (a&c) | b')
self.assertNotEqual(t1, t2)
self.assertEqual(t1.flatten(), t2)
def test_parse_raise_ParseError(self):
algebra = BooleanAlgebra()
invalid_expressions = [
'l-a AND none',
'(l-a + AND l-b',
'(l-a + AND l-b)',
'(l-a AND l-b',
'(l-a + AND l-b))',
'(l-a AND l-b))',
'l-a AND',
'OR l-a',
'+ l-a',
]
for expr in invalid_expressions:
print(expr)
try:
algebra.parse(expr)
self.fail("Exception should be raised when parsing '%s'" % expr)
except ParseError:
pass
def test_complex_expression_without_parens_parsed_or_built_in_python_should_be_identical(self):
# FIXME: THIS SHOULD NOT FAIL
algebra = BooleanAlgebra()
a = algebra.Symbol('a')
b = algebra.Symbol('b')
c = algebra.Symbol('c')
d = algebra.Symbol('d')
test_expression_str = '''
~a&~b&~c&~d | ~a&~b&~c&d | ~a&b&~c&~d |
~a&b&c&d | ~a&b&~c&d | ~a&b&c&~d |
a&~b&~c&d | ~a&b&c&d | a&~b&c&d | a&b&c&d
'''
parsed = algebra.parse(test_expression_str)
test_expression = (
~a & ~b & ~c & ~d | ~a & ~b & ~c & d | ~a & b & ~c & ~d |
~ a & b & c & d | ~a & b & ~c & d | ~a & b & c & ~d |
a & ~b & ~c & d | ~a & b & c & d | a & ~b & c & d | a & b & c & d
)
self.assertEqual(parsed.pretty(), test_expression.pretty())
def test_simplify(self):
algebra = BooleanAlgebra()
a = algebra.Symbol('a')
b = algebra.Symbol('b')
c = algebra.Symbol('c')
_0 = algebra.FALSE
_1 = algebra.TRUE
# Idempotence
self.assertEqual(a, (a & a).simplify())
# Idempotence + Associativity
self.assertEqual(a | b, (a | (a | b)).simplify())
# Annihilation
self.assertEqual(_0, (a & _0).simplify())
self.assertEqual(_1, (a | _1).simplify())
# Identity
self.assertEqual(a, (a & _1).simplify())
self.assertEqual(a, (a | _0).simplify())
# Complementation
self.assertEqual(_0, (a & ~a).simplify())
self.assertEqual(_1, (a | ~a).simplify())
# Absorption
self.assertEqual(a, (a & (a | b)).simplify())
self.assertEqual(a, (a | (a & b)).simplify())
self.assertEqual(b & a, ((b & a) | (b & a & c)).simplify())
# Elimination
self.assertEqual(a, ((a & ~b) | (a & b)).simplify())
expected = algebra.parse('(a&b)|(b&c)|(a&c)')
result = algebra.parse('(~a&b&c) | (a&~b&c) | (a&b&~c) | (a&b&c)', simplify=True)
self.assertEqual(expected, result)
expected = algebra.parse('b&d')
result = algebra.parse('(a&b&c&d) | (b&d)', simplify=True)
self.assertEqual(expected, result)
expected = algebra.parse('(~b&~d&a) | (~c&~d&b) | (a&c&d)', simplify=True)
result = algebra.parse('''(~a&b&~c&~d) | (a&~b&~c&~d) | (a&~b&c&~d) |
(a&~b&c&d) | (a&b&~c&~d) | (a&b&c&d)''', simplify=True)
self.assertEqual(expected.pretty(), result.pretty())
def test_parse(self):
algebra = BooleanAlgebra()
a, b, c = algebra.Symbol('a'), algebra.Symbol('b'), algebra.Symbol('c')
self.assertEqual(algebra.parse('0'), algebra.FALSE)
self.assertEqual(algebra.parse('(0)'), algebra.FALSE)
self.assertEqual(algebra.parse('1') , algebra.TRUE)
self.assertEqual(algebra.parse('(1)'), algebra.TRUE)
self.assertEqual(algebra.parse('a'), a)
self.assertEqual(algebra.parse('(a)'), a)
self.assertEqual(algebra.parse('(a)'), a)
self.assertEqual(algebra.parse('~a'), algebra.parse('~(a)'))
self.assertEqual(algebra.parse('~(a)'), algebra.parse('(~a)'))
self.assertEqual(algebra.parse('~a'), ~a)
self.assertEqual(algebra.parse('(~a)'), ~a)
self.assertEqual(algebra.parse('~~a', simplify=True), (~~a).simplify())
self.assertEqual(algebra.parse('a&b'), a & b)
self.assertEqual(algebra.parse('~a&b'), ~a & b)
self.assertEqual(algebra.parse('a&~b'), a & ~b)
self.assertEqual(algebra.parse('a&b&c'), algebra.parse('a&b&c'))
self.assertEqual(algebra.parse('a&b&c'), algebra.AND(a, b, c))
self.assertEqual(algebra.parse('~a&~b&~c'), algebra.parse('~a&~b&~c'))
self.assertEqual(algebra.parse('~a&~b&~c'), algebra.AND(~a, ~b, ~c))
self.assertEqual(algebra.parse('a|b'), a | b)
self.assertEqual(algebra.parse('~a|b'), ~a | b)
self.assertEqual(algebra.parse('a|~b'), a | ~b)
self.assertEqual(algebra.parse('a|b|c'), algebra.parse('a|b|c'))
self.assertEqual(algebra.parse('a|b|c'), algebra.OR(a, b, c))
self.assertEqual(algebra.parse('~a|~b|~c'), algebra.OR(~a, ~b, ~c))
self.assertEqual(algebra.parse('(a|b)'), a | b)
self.assertEqual(algebra.parse('a&(a|b)', simplify=True), (a & (a | b)).simplify())
self.assertEqual(algebra.parse('a&(a|~b)', simplify=True), (a & (a | ~b)).simplify())
self.assertEqual(algebra.parse('(a&b)|(b&((c|a)&(b|(c&a))))', simplify=True), ((a & b) | (b & ((c | a) & (b | (c & a))))).simplify())
self.assertEqual(algebra.parse('(a&b)|(b&((c|a)&(b|(c&a))))', simplify=True), algebra.parse('a&b | b&(c|a)&(b|c&a)', simplify=True))
def test_objects_return_set_of_unique_Symbol_objs(self):
alg = BooleanAlgebra()
exp = alg.parse('a and b or a and c')
assert set(['a', 'b', 'c']) == exp.objects
def test_literals_return_set_of_unique_literals(self):
alg = BooleanAlgebra()
exp = alg.parse('a and b or a and c')
assert set([alg.Symbol('a'), alg.Symbol('b'), alg.Symbol('c')]) == exp.literals
def test_get_symbols_return_all_symbols_in_original_order(self):
alg = BooleanAlgebra()
exp = alg.parse('a and b or True and a and c')
assert [alg.Symbol('a'), alg.Symbol('b'), alg.Symbol('a'), alg.Symbol('c')] == exp.get_symbols()
def test_isliteral(self):
algebra = BooleanAlgebra()
s = algebra.Symbol(1)
self.assertTrue(algebra.NOT(s).isliteral)
self.assertFalse(algebra.parse('~(a|b)').isliteral)
def test_annihilator(self):
algebra = BooleanAlgebra()
self.assertEqual(algebra.parse('a&a').annihilator, algebra.FALSE)
self.assertEqual(algebra.parse('a|a').annihilator, algebra.TRUE)
def test_identity(self):
algebra = BooleanAlgebra()
self.assertEqual(algebra.parse('a|b').identity, algebra.FALSE)
self.assertEqual(algebra.parse('a&b').identity, algebra.TRUE)
def test_normalize(self):
algebra = BooleanAlgebra()
expr = algebra.parse('((s|a)&(s|b)&(s|c)&(s|d)&(e|c|d))|(a&e&d)')
result = algebra.normalize(expr, expr.AND)
expected = algebra.parse('(a|s)&(b|e|s)&(c|d|e)&(c|e|s)&(d|s)')
self.assertEqual(result, expected)
def test_creation(self):
algebra = BooleanAlgebra()
expr_str = '(a|b|c)&d&(~e|(f&g))'
expr = algebra.parse(expr_str)
self.assertEqual(expr_str, str(expr))
