diff options
| -rw-r--r-- | docs/changelog.rst | 4 | ||||
| -rw-r--r-- | docs/fuzzy.rst | 30 | ||||
| -rw-r--r-- | factory/fuzzy.py | 35 | ||||
| -rw-r--r-- | tests/test_fuzzy.py | 50 |
4 files changed, 97 insertions, 22 deletions
diff --git a/docs/changelog.rst b/docs/changelog.rst index 018ec60..ebe9930 100644 --- a/docs/changelog.rst +++ b/docs/changelog.rst @@ -7,6 +7,10 @@ ChangeLog 2.5.0 (master) -------------- +*New:* + + - Add support for getting/setting :mod:`factory.fuzzy`'s random state (see :issue:`175`, :issue:`185`). + *Deprecation:* - Remove deprecated features from :ref:`v2.4.0` diff --git a/docs/fuzzy.rst b/docs/fuzzy.rst index 1480419..0658652 100644 --- a/docs/fuzzy.rst +++ b/docs/fuzzy.rst @@ -338,3 +338,33 @@ They should inherit from the :class:`BaseFuzzyAttribute` class, and override its The method responsible for generating random values. *Must* be overridden in subclasses. + + +Managing randomness +------------------- + +Using :mod:`random` in factories allows to "fuzz" a program efficiently. +However, it's sometimes required to *reproduce* a failing test. + +:mod:`factory.fuzzy` uses a separate instance of :class:`random.Random`, +and provides a few helpers for this: + +.. method:: get_random_state() + + Call :meth:`get_random_state` to retrieve the random generator's current + state. + +.. method:: set_random_state(state) + + Use :meth:`set_random_state` to set a custom state into the random generator + (fetched from :meth:`get_random_state` in a previous run, for instance) + +.. method:: reseed_random(seed) + + The :meth:`reseed_random` function allows to load a chosen seed into the random generator. + + +Custom :class:`BaseFuzzyAttribute` subclasses **SHOULD** +use :obj:`factory.fuzzy._random` foras a randomness source; this ensures that +data they generate can be regenerated using the simple state from +:meth:`get_random_state`. diff --git a/factory/fuzzy.py b/factory/fuzzy.py index 94599b7..0137ba9 100644 --- a/factory/fuzzy.py +++ b/factory/fuzzy.py @@ -34,6 +34,25 @@ from . import compat from . import declarations +_random = random.Random() + + +def get_random_state(): + """Retrieve the state of factory.fuzzy's random generator.""" + return _random.getstate() + + +def set_random_state(state): + """Force-set the state of factory.fuzzy's random generator.""" + return _random.setstate(state) + + +def reseed_random(seed): + """Reseed factory.fuzzy's random generator.""" + r = random.Random(seed) + set_random_state(r.getstate()) + + class BaseFuzzyAttribute(declarations.OrderedDeclaration): """Base class for fuzzy attributes. @@ -81,7 +100,7 @@ class FuzzyText(BaseFuzzyAttribute): """ def __init__(self, prefix='', length=12, suffix='', - chars=string.ascii_letters, **kwargs): + chars=string.ascii_letters, **kwargs): super(FuzzyText, self).__init__(**kwargs) self.prefix = prefix self.suffix = suffix @@ -89,7 +108,7 @@ class FuzzyText(BaseFuzzyAttribute): self.chars = tuple(chars) # Unroll iterators def fuzz(self): - chars = [random.choice(self.chars) for _i in range(self.length)] + chars = [_random.choice(self.chars) for _i in range(self.length)] return self.prefix + ''.join(chars) + self.suffix @@ -101,7 +120,7 @@ class FuzzyChoice(BaseFuzzyAttribute): super(FuzzyChoice, self).__init__(**kwargs) def fuzz(self): - return random.choice(self.choices) + return _random.choice(self.choices) class FuzzyInteger(BaseFuzzyAttribute): @@ -119,7 +138,7 @@ class FuzzyInteger(BaseFuzzyAttribute): super(FuzzyInteger, self).__init__(**kwargs) def fuzz(self): - return random.randrange(self.low, self.high + 1, self.step) + return _random.randrange(self.low, self.high + 1, self.step) class FuzzyDecimal(BaseFuzzyAttribute): @@ -137,7 +156,7 @@ class FuzzyDecimal(BaseFuzzyAttribute): super(FuzzyDecimal, self).__init__(**kwargs) def fuzz(self): - base = compat.float_to_decimal(random.uniform(self.low, self.high)) + base = compat.float_to_decimal(_random.uniform(self.low, self.high)) return base.quantize(decimal.Decimal(10) ** -self.precision) @@ -155,7 +174,7 @@ class FuzzyFloat(BaseFuzzyAttribute): super(FuzzyFloat, self).__init__(**kwargs) def fuzz(self): - return random.uniform(self.low, self.high) + return _random.uniform(self.low, self.high) class FuzzyDate(BaseFuzzyAttribute): @@ -175,7 +194,7 @@ class FuzzyDate(BaseFuzzyAttribute): self.end_date = end_date.toordinal() def fuzz(self): - return datetime.date.fromordinal(random.randint(self.start_date, self.end_date)) + return datetime.date.fromordinal(_random.randint(self.start_date, self.end_date)) class BaseFuzzyDateTime(BaseFuzzyAttribute): @@ -215,7 +234,7 @@ class BaseFuzzyDateTime(BaseFuzzyAttribute): delta = self.end_dt - self.start_dt microseconds = delta.microseconds + 1000000 * (delta.seconds + (delta.days * 86400)) - offset = random.randint(0, microseconds) + offset = _random.randint(0, microseconds) result = self.start_dt + datetime.timedelta(microseconds=offset) if self.force_year is not None: diff --git a/tests/test_fuzzy.py b/tests/test_fuzzy.py index 1caeb0a..fd32705 100644 --- a/tests/test_fuzzy.py +++ b/tests/test_fuzzy.py @@ -55,7 +55,7 @@ class FuzzyChoiceTestCase(unittest.TestCase): d = fuzzy.FuzzyChoice(options) - with mock.patch('random.choice', fake_choice): + with mock.patch('factory.fuzzy._random.choice', fake_choice): res = d.evaluate(2, None, False) self.assertEqual(6, res) @@ -93,7 +93,7 @@ class FuzzyIntegerTestCase(unittest.TestCase): fuzz = fuzzy.FuzzyInteger(2, 8) - with mock.patch('random.randrange', fake_randrange): + with mock.patch('factory.fuzzy._random.randrange', fake_randrange): res = fuzz.evaluate(2, None, False) self.assertEqual((2 + 8 + 1) * 1, res) @@ -103,7 +103,7 @@ class FuzzyIntegerTestCase(unittest.TestCase): fuzz = fuzzy.FuzzyInteger(8) - with mock.patch('random.randrange', fake_randrange): + with mock.patch('factory.fuzzy._random.randrange', fake_randrange): res = fuzz.evaluate(2, None, False) self.assertEqual((0 + 8 + 1) * 1, res) @@ -113,7 +113,7 @@ class FuzzyIntegerTestCase(unittest.TestCase): fuzz = fuzzy.FuzzyInteger(5, 8, 3) - with mock.patch('random.randrange', fake_randrange): + with mock.patch('factory.fuzzy._random.randrange', fake_randrange): res = fuzz.evaluate(2, None, False) self.assertEqual((5 + 8 + 1) * 3, res) @@ -146,7 +146,7 @@ class FuzzyDecimalTestCase(unittest.TestCase): fuzz = fuzzy.FuzzyDecimal(2.0, 8.0) - with mock.patch('random.uniform', fake_uniform): + with mock.patch('factory.fuzzy._random.uniform', fake_uniform): res = fuzz.evaluate(2, None, False) self.assertEqual(decimal.Decimal('10.0'), res) @@ -156,7 +156,7 @@ class FuzzyDecimalTestCase(unittest.TestCase): fuzz = fuzzy.FuzzyDecimal(8.0) - with mock.patch('random.uniform', fake_uniform): + with mock.patch('factory.fuzzy._random.uniform', fake_uniform): res = fuzz.evaluate(2, None, False) self.assertEqual(decimal.Decimal('8.0'), res) @@ -166,7 +166,7 @@ class FuzzyDecimalTestCase(unittest.TestCase): fuzz = fuzzy.FuzzyDecimal(8.0, precision=3) - with mock.patch('random.uniform', fake_uniform): + with mock.patch('factory.fuzzy._random.uniform', fake_uniform): res = fuzz.evaluate(2, None, False) self.assertEqual(decimal.Decimal('8.001').quantize(decimal.Decimal(10) ** -3), res) @@ -214,7 +214,7 @@ class FuzzyDateTestCase(unittest.TestCase): fake_randint = lambda low, high: (low + high) // 2 fuzz = fuzzy.FuzzyDate(self.jan1, self.jan31) - with mock.patch('random.randint', fake_randint): + with mock.patch('factory.fuzzy._random.randint', fake_randint): res = fuzz.evaluate(2, None, False) self.assertEqual(datetime.date(2013, 1, 16), res) @@ -225,7 +225,7 @@ class FuzzyDateTestCase(unittest.TestCase): fuzz = fuzzy.FuzzyDate(self.jan1) fake_randint = lambda low, high: (low + high) // 2 - with mock.patch('random.randint', fake_randint): + with mock.patch('factory.fuzzy._random.randint', fake_randint): res = fuzz.evaluate(2, None, False) self.assertEqual(datetime.date(2013, 1, 2), res) @@ -332,7 +332,7 @@ class FuzzyNaiveDateTimeTestCase(unittest.TestCase): fake_randint = lambda low, high: (low + high) // 2 fuzz = fuzzy.FuzzyNaiveDateTime(self.jan1, self.jan31) - with mock.patch('random.randint', fake_randint): + with mock.patch('factory.fuzzy._random.randint', fake_randint): res = fuzz.evaluate(2, None, False) self.assertEqual(datetime.datetime(2013, 1, 16), res) @@ -343,7 +343,7 @@ class FuzzyNaiveDateTimeTestCase(unittest.TestCase): fuzz = fuzzy.FuzzyNaiveDateTime(self.jan1) fake_randint = lambda low, high: (low + high) // 2 - with mock.patch('random.randint', fake_randint): + with mock.patch('factory.fuzzy._random.randint', fake_randint): res = fuzz.evaluate(2, None, False) self.assertEqual(datetime.datetime(2013, 1, 2), res) @@ -450,7 +450,7 @@ class FuzzyDateTimeTestCase(unittest.TestCase): fake_randint = lambda low, high: (low + high) // 2 fuzz = fuzzy.FuzzyDateTime(self.jan1, self.jan31) - with mock.patch('random.randint', fake_randint): + with mock.patch('factory.fuzzy._random.randint', fake_randint): res = fuzz.evaluate(2, None, False) self.assertEqual(datetime.datetime(2013, 1, 16, tzinfo=compat.UTC), res) @@ -461,7 +461,7 @@ class FuzzyDateTimeTestCase(unittest.TestCase): fuzz = fuzzy.FuzzyDateTime(self.jan1) fake_randint = lambda low, high: (low + high) // 2 - with mock.patch('random.randint', fake_randint): + with mock.patch('factory.fuzzy._random.randint', fake_randint): res = fuzz.evaluate(2, None, False) self.assertEqual(datetime.datetime(2013, 1, 2, tzinfo=compat.UTC), res) @@ -486,7 +486,7 @@ class FuzzyTextTestCase(unittest.TestCase): chars = ['a', 'b', 'c'] fuzz = fuzzy.FuzzyText(prefix='pre', suffix='post', chars=chars, length=4) - with mock.patch('random.choice', fake_choice): + with mock.patch('factory.fuzzy._random.choice', fake_choice): res = fuzz.evaluate(2, None, False) self.assertEqual('preaaaapost', res) @@ -504,3 +504,25 @@ class FuzzyTextTestCase(unittest.TestCase): for char in res: self.assertIn(char, ['a', 'b', 'c']) + + +class FuzzyRandomTestCase(unittest.TestCase): + def test_seeding(self): + fuzz = fuzzy.FuzzyInteger(1, 1000) + + fuzzy.reseed_random(42) + value = fuzz.evaluate(sequence=1, obj=None, create=False) + + fuzzy.reseed_random(42) + value2 = fuzz.evaluate(sequence=1, obj=None, create=False) + self.assertEqual(value, value2) + + def test_reset_state(self): + fuzz = fuzzy.FuzzyInteger(1, 1000) + + state = fuzzy.get_random_state() + value = fuzz.evaluate(sequence=1, obj=None, create=False) + + fuzzy.set_random_state(state) + value2 = fuzz.evaluate(sequence=1, obj=None, create=False) + self.assertEqual(value, value2) |