Medium - Hypothesis example test for is_plaindrome

test_hypothesis.py

"""Basic pytest+hypothesis for ``is_palindrome`` method."""

from typing import Any, Callable

from hypothesis import given, assume
from hypothesis.strategies import text, composite


def is_palindrome(string: str) -> bool:
    """Determine if a given string is a palindrome.

    :param str string: The string to process
    :return: True if given string is a palindrome, otherwise False
    :rtype: bool
    """
    return string == string[::-1]


@composite
def palindrome(draw: Callable[..., Any]) -> str:
    """Composite hypothesis strategy for palindrome strings.

    :param Callable[..., Any] draw: Function for drawing from hypothesis strategies
    :return: A palindrome string
    :rtype: str
    """
    partial_content = draw(text())
    return partial_content + partial_content[::-1]


@composite
def not_palindrome(draw: Callable[..., Any]) -> str:
    """Composite hypothesis strategy for non-palindrome strings.

    :param Callable[..., Any] draw: Function for drawing from hypothesis strategies
    :return: A non-palindrome string
    :rtype: str
    """
    prefix_content = draw(text(min_size=2))
    assume(len(set(prefix_content)) > 1)
    return prefix_content + prefix_content[::-1][:-1]


@given(palindrome())
def test_is_plaindrome(palindrome):
    """Test true cases for ``is_palindrome``.

    :param str palindrome: A palindrome string
    """
    assert is_palindrome(palindrome)


@given(not_palindrome())
def test_not_is_palindrome(not_palindrome):
    """Test false cases for ``is_plaindrome``.

    :param str not_palindrome: A non-palindrome string
    """
    assert not is_palindrome(not_palindrome)