Что такое property-based тестирование (Hypothesis)?python-61

pip install hypothesis

from hypothesis import given
import hypothesis.strategies as st

@given(st.integers(), st.integers())
def test_add_commutative(a, b):
    assert a + b == b + a  # Коммутативность сложения

import hypothesis.strategies as st

# Целые числа
st.integers(min_value=1, max_value=100)

# Строки
st.text(alphabet='abc', min_size=1, max_size=5)

# Списки
st.lists(st.integers(), min_size=1)

# Словари
st.dictionaries(st.text(), st.integers())

# Кастомные типы
st.builds(Person, name=st.text(), age=st.integers())

@given(st.lists(st.integers()))
def test_sort_properties(lst):
    sorted_lst = sorted(lst)
    # Проверяем длину
    assert len(sorted_lst) == len(lst)
    # Проверяем порядок
    assert all(sorted_lst[i] <= sorted_lst[i+1] for i in range(len(sorted_lst)-1))
    # Проверяем мультимножество
    assert collections.Counter(sorted_lst) == collections.Counter(lst)

@given(
    st.integers(min_value=0, max_value=1000),
    st.integers(min_value=0, max_value=1000)
)
def test_account_invariants(deposit, withdraw):
    account = Account(balance=1000)
    account.deposit(deposit)
    try:
        account.withdraw(withdraw)
    except InsufficientFunds:
        pass

    assert account.balance >= 0  # Инвариант: баланс не может быть отрицательным

@st.composite
def user_strategy(draw):
    name = draw(st.text(min_size=1))
    age = draw(st.integers(min_value=18, max_value=120))
    return {"name": name, "age": age}

@given(user_strategy())
def test_user_validation(user):
    assert validate_user(user["name"], user["age"])

from hypothesis.stateful import RuleBasedStateMachine, rule

class AccountTest(RuleBasedStateMachine):
    def __init__(self):
        super().__init__()
        self.account = Account(balance=0)

    @rule(amount=st.integers(min_value=1))
    def deposit(self, amount):
        self.account.deposit(amount)
        assert self.account.balance >= 0

    @rule(amount=st.integers(min_value=1))
    def withdraw(self, amount):
        try:
            self.account.withdraw(amount)
        except InsufficientFunds:
            pass
        assert self.account.balance >= 0

TestAccount = AccountTest.TestCase

from hypothesis import settings, HealthCheck

@settings(
    max_examples=500,
    suppress_health_check=[HealthCheck.too_slow]
)
@given(st.integers())
def test_large_range(x):
    assert x * 0 == 0

from hypothesis import example

@given(st.text())
@example("")
@example("a")
@example("test@example.com")
def test_email_validation(email):
    result = validate_email(email)
    assert result == ("@" in email)