pytestの使い方。ディレクトリ構成やライブラリなど実践で使えるレベルまで

======================================================== test session starts ========================================================
platform darwin -- Python 3.11.2, pytest-7.4.0, pluggy-1.2.0
rootdir: /pytest
collected 0 items

======================================================= no tests ran in 0.00s =======================================================
(pytest-sample)

def say_hello():
    return 'Hello, World!'

def test_say_hello():
    assert say_hello() == 'Hello, World!'

======================================================== test session starts ========================================================
platform darwin -- Python 3.11.2, pytest-7.4.0, pluggy-1.2.0
rootdir: /pytest
collected 1 item

hello_test.py .                                                                                                               [100%]

========================================================= 1 passed in 0.00s =========================================================
(pytest-sample)

def fail():
    return 1

def test_fail():
    assert fail() == 0

======================================================== test session starts ========================================================
platform darwin -- Python 3.11.2, pytest-7.4.0, pluggy-1.2.0
rootdir: /pytest
collected 1 item

fail_test.py F                                                                                                                [100%]

============================================================= FAILURES ==============================================================
_____________________________________________________________ test_fail _____________________________________________________________

    def test_fail():
>       assert fail() == 0
E       assert 1 == 0
E        +  where 1 = fail()

fail_test.py:5: AssertionError
====================================================== short test summary info ======================================================
FAILED fail_test.py::test_fail - assert 1 == 0
========================================================= 1 failed in 0.01s =========================================================
(pytest-sample)

def test_hello():
    word = 'world'
    assert word == 'hello', 'helloと言っていない'

FAILED test_hello.py::test_hello - AssertionError: helloと言っていない

def divide(a, b):
    return a / b

from src.devide import devide
import pytest


def test_devide_by_zero():
    with pytest.raises(ZeroDivisionError):
        devide(1, 0)

def test_divide_by_zero_message():
    with pytest.raises(ZeroDivisionError, match="division by zero"):
        divide(1, 0)

@pytest.fixture
def sample_data():
    return {"key": "value"}

@pytest.mark.slow
def test_slow_function():
    pass

@pytest.mark.skip(reason="スキップします")
def test_example():
    pass

@pytest.mark.skipif(sys.version_info < (3,7), reason="Python3.7以上のバージョンが必要です")
def test_example():
    pass

@pytest.mark.parametrize("x, y, expected", [(1, 2, 3), (4, 5, 9)])
def test_add(x, y, expected):
    assert x + y == expected

@pytest.mark.xfail
def test_example():
    assert False

.
├── README.md
├── requirements.txt
├── setup.py
├── src
│   └── mymodule
│       └── mymodule.py
└── tests
    ├── __init__.py
    ├── conftest.py
    ├── fixtures
    ├── integration
    └── unit
        └── mymodule
            └── test_mymodule.py

class MyModule(object):
    def __init__(self):
        pass

    def add(self, a, b):
        return a + b

from src.mymodule.mymodule import MyModule


def test_module():
    mymodule = MyModule()
    assert mymodule.add(1, 2) == 3

from src.mymodule.mymodule import MyModule


class TestMyModule(object):
    def test_module():
        mymodule = MyModule()
        assert mymodule.add(1, 2) == 3

import pytest

class SimpleDatabase:
    def __init__(self):
        self.connection = None

    def connect(self):
        # 接続状態
        self.connection = "Connected"

    def close(self):
        # 接続終了状態
        self.connection = None

@pytest.fixture
def database():
    # セットアップ: データベース接続
    db = SimpleDatabase()
    db.connect()

    yield db  # テストにデータベースインスタンスを返す

    # ティアダウン: データベース接続終了
    db.close()

def test_database_connection(database):
    assert database.connection == "Connected"

def test_database_func(database):
    pass

# テスト終了後はティアダウンで接続が失われた状態

import pytest

# 共有するフィクスチャの定義
@pytest.fixture
def database():
    db = connect_to_database()
    yield db
    db.close()

# フックの定義
def pytest_configure(config):
    config.addinivalue_line("markers", "slow: marks tests as slow")

# カスタムオプションの定義
def pytest_addoption(parser):
    parser.addoption("--myoption", action="store", default="default_value", help="カスタムオプション")

@pytest.fixture
def myoption(request):
    return request.config.getoption("--myoption")

# テストデータの共有
@pytest.fixture
def common_data():
    return {"key": "value"}

def test_database_func(database):
    pass

def test_myoption_receive(myoption):
    assert myoption == "test"

import random
import string


def random_string(length=10):
    """固定幅のランダム文字列を生成"""
    letters = string.ascii_lowercase
    return ''.join(random.choice(letters) for i in range(length))

def generate_user():
    """ランダムなユーザーデータ生成"""
    return {
        "username": random_string(8),
        "password": random_string(12),
        "email": f"{random_string(5)}@example.com"
    }

from utils import generate_user
import pytest


def test_user_registration():
    user = generate_user()
    # このデータを使ってユーザー登録の実装をテストする
    # ユーザー登録機能がTrueかどうかをassert

def test_user_login():
    user = generate_user()
    # ログインをテスト

from src.mymodule.mymodule import MyModule
import pytest


class TestMyModule(object):
    # これは2番目に実行
    @pytest.mark.run(order=2)
    def test_module_one(self):
        mymodule = MyModule()
        assert mymodule.add(1, 2) == 3

    # これは最初に実行
    @pytest.mark.run(order=1)
    def test_module_two(self):
        mymodule = MyModule()
        assert mymodule.subtract(1, 2) == -1

tests/integration/mymodule/test_mymodule.py::TestMyModule::test_module_two PASSED  [ 50%]
tests/integration/mymodule/test_mymodule.py::TestMyModule::test_module_one PASSED  [100%]

.
├── mymodule.py
└── tests
    ├── __init__.py
    └── test_mymodule.py

def add(a, b):
    return a + b

def subtract(a, b):
    return a - b

def not_tested_func():
    pass

from mymodule import add, subtract


def test_add():
    assert add(1, 2) == 3

def test_subtract():
    assert subtract(3, 2) == 1

collected 2 items

tests/test_mymodule.py ..                                                                                                     [100%]

---------- coverage: platform darwin, python 3.11.2-final-0 ----------
Name          Stmts   Miss  Cover
---------------------------------
mymodule.py       6      1    83%
---------------------------------
TOTAL             6      1    83%

from mymodule import add, subtract

def test_add():
    assert add(1, 2) == 3

def test_subtract():
    assert subtract(3, 2) == 1

def test_failure():
    assert 1 == 2

.
├── mymodule.py
└── tests
    ├── data
    │   └── test1.txt
    ├── test_mymodule
    │   └── test2.txt
    └── test_mymodule.py

def test_read_data_file1(shared_datadir):
    # datadirはpathlib.Pathオブジェクト
    data_file = shared_datadir / 'test1.txt'

    with open(data_file, 'r') as f:
        content = f.read()

    # 実験のため単純にデータが空でないことを確認
    assert content

def test_read_data_file2(datadir):
    data_file = datadir / 'test2.txt'

    with open(data_file, 'r') as f:
        content = f.read()

    assert content

test1

test2

import requests


def get_website_title(url):
    response = requests.get(url)
    if response.status_code == 200:
        return response.text.split('<title>')[1].split('</title>')[0]
    else:
        return None

from mymodule import get_website_title


def test_get_website_title(mocker):
    # `text`と200の`status_code`を要素としてモックレスポンスを作成
    mock_response = mocker.Mock()
    mock_response.text = "<html><head><title>モックテストタイトル</title></head></html>"
    mock_response.status_code = 200

    # requests.get()をモック化し、モックレスポンスを返すように設定
    mocker.patch('requests.get', return_value=mock_response)

    # 実際のHTTPリクエストをお叶わずに"モックテストタイトル"を取得
    result = get_website_title("http://mock.url")
    assert result == "モックテストタイトル"