Postman to Python - Api Testing

# ----------------   api_client.py ----------------

# pip install requests
import time
from requests import session


class ApiClient:

    user_name = None
    user_pass = None
    user_id = None

    def __init__(self):
        self.client = session()
        self.host = "https://demoqa.com"

    def request(self, method, url, **kwargs) -> dict | None:
        time.sleep(0.5)  # slow down not to ddos 3rd party server

        res = self.client.request(method, f"{self.host}/{url}", **kwargs)
        res.raise_for_status()
        if res.text:
            return res.json()

    def get_books(self):
        return self.request("GET", "BookStore/v1/Books")

    def create_user(self):
        payload = {"userName": self.user_name,
                   "password": self.user_pass}
        return self.request("POST", "Account/v1/User", json=payload)

    def create_token(self):
        payload = {"userName": self.user_name,
                   "password": self.user_pass}
        return self.request("POST", "Account/v1/GenerateToken", json=payload)

    def user_login(self):
        payload = {"userName": self.user_name,
                   "password": self.user_pass}
        return self.request("POST", "Account/v1/Login", json=payload)

    def get_user(self):
        return self.request("GET", f"Account/v1/User/{self.user_id}")

    def add_books(self, *isbns: str):
        payload = {"userId": self.user_id,
                   "collectionOfIsbns": [{"isbn": i} for i in isbns]}
        return self.request("POST", "BookStore/v1/Books", json=payload)

    def delete_book(self, isbn):
        payload = {"isbn": isbn,
                   "userId": self.user_id}
        return self.request("DELETE", "BookStore/v1/Book", json=payload)

    def swap_books(self, isbn1, isbn2):
        payload = {"userId": self.user_id,
                   "isbn": isbn2}
        return self.request("PUT", f"BookStore/v1/Books/{isbn1}", json=payload)

    def delete_books(self):
        params = {"UserId": self.user_id}
        return self.request("DELETE", f"BookStore/v1/Books", params=params)

    def delete_user(self):
        return self.request("DELETE", f"Account/v1/User/{self.user_id}")

    def setup(self, user_name, user_pass):
        self.user_name = user_name
        self.user_pass = user_pass
        self.create_user()
        self.create_token()

        res = self.user_login()
        self.user_id = res["userId"]
        self.client.headers["Authorization"] = f"Bearer {res['token']}"



# -------------  test_sample.py -----------------------


import os
import pytest
from api_client import ApiClient

USER_NAME = os.environ.get("API_TEST_USER_NAME")
PASSWORD = os.environ.get("API_TEST_USER_PASSWORD")


@pytest.fixture
def client():
    client = ApiClient()
    client.setup(USER_NAME, PASSWORD)
    yield client
    client.delete_user()


@pytest.fixture(scope="session")
def books():
    return ApiClient().get_books()["books"]


def test_full(client, books):
    client.get_user()
    client.add_books(books[0]["isbn"], books[1]["isbn"])
    client.delete_book(books[0]["isbn"])
    client.replace_book(books[1]["isbn"], books[2]["isbn"])
    client.delete_books()


def test_get_books():
    res = ApiClient().get_books()
    assert len(res["books"]) == 8


def test_get_profile(client):
    res = client.get_user()
    assert res["userId"] == client.user_id
    assert res["username"] == client.user_name
    assert len(res["books"]) == 0


def test_add_books(client, books):
    isbn1 = books[0]["isbn"]
    isbn2 = books[1]["isbn"]

    res = client.add_books(isbn1, isbn2)
    assert res["books"] == [{'isbn': isbn1}, {'isbn': isbn2}]

    res = client.get_user()
    assert len(res["books"]) == 2
    assert res["books"][0]["isbn"] == isbn1
    assert res["books"][1]["isbn"] == isbn2


def test_delete_books(client, books):
    isbn1 = books[0]["isbn"]
    isbn2 = books[1]["isbn"]
    client.add_books(isbn1, isbn2)

    client.delete_books()
    res = client.get_user()
    assert len(res["books"]) == 0