clean_code.py

import pytest


class Hat:

    def __init__(self, color: str) -> None:
        self.hat_color = color

    def suits(self, style: str):
        return self.hat_color == style


class Weather:

    def __init__(self, rainy: bool) -> None:
        self.rainy = rainy
        self.sunny = not rainy

    def is_raining(self):
        return self.rainy


def should_i_wear_this_hat(hat, weather):
    res = False
    if isinstance(hat, Hat):
        current_fashion = _get_fashion()
        weather_outside = weather
        is_stylish = evaluate_style(hat, current_fashion)
        if weather_outside.is_raining():
            res = True
            if res is True:
                print("Damn!")
            return res
        else:
            res = is_stylish
            print("Nice!")
            return res
    else:
        return res


def _get_fashion():
    return ["green", "blue", "purple", "yellow"]


def evaluate_style(hat, current_fashion):
    if len(current_fashion) > 0:
        for f in current_fashion:
            if hat.suits(f):
                return True
        return False
    else:
        return False  # User Error


def test_cannot_wear_anything_other_than_a_hat():
    no_hat = "foo"
    assert should_i_wear_this_hat(no_hat, Weather(False)) is False


def test_should_wear_any_hat_if_weather_is_rainy():
    assert should_i_wear_this_hat(Hat("black"), Weather(True)) is True


class TestSunnyWeather:

    @pytest.fixture
    def sunny_weather(self):
        return Weather(False)

    def test_should_not_wear_hat_if_it_is_not_stylish(self, sunny_weather):
        assert should_i_wear_this_hat(Hat("black"), sunny_weather) is False

    @pytest.mark.parametrize("stylish_color", [
        "green",
        "blue",
        "purple",
        "yellow"
    ])
    def test_should_wear_hat_if_it_has_stylish_color(self, stylish_color, sunny_weather):
        assert should_i_wear_this_hat(Hat(stylish_color), sunny_weather) is True