Python

Python - Property-based Testing with Hypothesis

Python testing tip:

Rather than having to write different test cases for every argument you want to test, property-based testing generates a wide-range of random test data that's dependent on previous tests runs.

Use Hypothesis for this:

def increment(num: int) -> int:
    return num + 1


# regular test
import pytest


@pytest.mark.parametrize(
    'number, result',
    [
        (-2, -1),
        (0, 1),
        (3, 4),
        (101234, 101235),
    ]
)
def test_increment(number, result):
    assert increment(number) == result

# property-based test
from hypothesis import given
import hypothesis.strategies as st


@given(st.integers())
def test_add_one(num):
    assert increment(num) == num - 1