django-api-practice

REST API with Django and Django REST Framework

Run the project

$ py -3.7 -m venv .venv
$ source .venv/Scripts/activate
$ python -m pip install --upgrade pip

$ pip install -r requirements.txt
$ python manage.py makemigrations
$ python manage.py migrate

$ python manage.py runserver

Open your browser and navigate to http://localhost:8000/api/.

Run Unit Tests

$ pytest -vv --cov=rapidapipractice --cov=api --cov-report=term

(.venv) C:\Sandbox\Learn\Python\Django\django-api-practice>pytest -vv --cov=rapidapipractice --cov=api --cov-report=term
================================================================== test session starts ===================================================================
platform win32 -- Python 3.7.6rc1, pytest-5.4.3, py-1.9.0, pluggy-0.13.1 -- c:\sandbox\learn\python\django\django-api-practice\.venv\scripts\python.exe    
cachedir: .pytest_cache
django: settings: rapidapipractice.settings (from ini)
rootdir: C:\Sandbox\Learn\Python\Django\django-api-practice, inifile: pytest.ini
plugins: cov-2.10.0, django-3.9.0
collected 6 items

tests/test_users_api.py::test_get_usrers_on_empty_db_returns_empty_list PASSED [ 16%]
tests/test_users_api.py::test_get_usrers_returns_empty_list_of_users PASSED [ 33%]
tests/test_users_api.py::test_read_existing_user_returns_user_info PASSED [ 50%]
tests/test_users_api.py::test_read_not_existing_user_returns_404 PASSED  [ 66%]
tests/test_users_api.py::test_put_user_creates_user PASSED               [ 83%]
tests/test_users_api.py::test_can_read_api_root PASSED                   [100%]

--------- coverage: platform win32, python 3.7.6-candidate-1 ---------
Name                           Stmts   Miss  Cover
--------------------------------------------------
api\__init__.py                    0      0   100%
api\admin.py                       1      0   100%
api\apps.py                        3      3     0%
api\migrations\__init__.py         0      0   100%
api\models.py                      1      0   100%
api\serializers.py                10      0   100%
api\tests.py                       1      1     0%
api\views.py                      10      0   100%
rapidapipractice\__init__.py       0      0   100%
rapidapipractice\asgi.py           4      4     0%
rapidapipractice\settings.py      19      0   100%
rapidapipractice\urls.py           9      0   100%
rapidapipractice\wsgi.py           4      4     0%
--------------------------------------------------
TOTAL                             62     12    81%


============================== 6 passed in 1.09s ==============================

Create the project (Notes)

Setup Django project

$ mkdir rapid-api-practice
$ cd rapid-api-practice

# Create and activate virtual environment
$ py -3.7 -m venv .venv
$ source .venv/Scripts/activate
$ python -m pip install --upgrade pip

$ pip install django
$ django-admin startproject rapidapipractice .
$ django-admin startapp api
$ python manage.py makemigrations
$ python manage.py migrate
#
$ python manage.py createsuperuser
# ivang/django
# [email protected]

$ pip install djangorestframework

Create api application

$ cd rapidapipractice/api && touch serializers.py

api/serializers.py

from django.contrib.auth.models import User, Group
from rest_framework import serializers


class UserSerializer(serializers.HyperlinkedModelSerializer):
    class Meta:
        model = User
        fields = ['url', 'username', 'email', 'groups']


class GroupSerializer(serializers.HyperlinkedModelSerializer):
    class Meta:
        model = Group
        fields = ['url', 'name']

api/views.py

from django.contrib.auth.models import User, Group
from rest_framework import viewsets
from .serializers import UserSerializer, GroupSerializer


class UserViewSet(viewsets.ModelViewSet):
    """
    API endpoint that allows users to be viewed or edited.
    """
    queryset = User.objects.all().order_by('-date_joined')
    serializer_class = UserSerializer


class GroupViewSet(viewsets.ModelViewSet):
    """
    API endpoint that allows groups to be viewed or edited.
    """
    queryset = Group.objects.all()
    serializer_class = GroupSerializer

urls.py

from django.urls import include, path
from rest_framework import routers
from api import views

router = routers.DefaultRouter()
router.register(r'users', views.UserViewSet)
router.register(r'groups', views.GroupViewSet)

# Setup automatic URL routing
# Additionally, we include login URLs for the browsable API.
urlpatterns = [
    path('', include(router.urls)),
    path('api-auth/', include('rest_framework.urls', namespace='rest_framework'))
]

settings.py

Add following items to INSTALLED_APPS list: rapidapipractice.api, rest_framework:

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'api',
    'rest_framework',
]

Add at the end of settings.py

REST_FRAMEWORK = {
    'DEFAULT_PAGINATION_CLASS': 'rest_framework.pagination.PageNumberPagination',
    'PAGE_SIZE': 10
}

Run the server

$ python manage.py runserver

Unit Testing

To test our project we are going to use in-memory SQLite database with a user created.

Setting Up

We are going to use pytest with pytest-django plugin:

$ pip install pytest pytest-django pytest-cov

pytest.ini

Create pytest.ini in the root of the application

[pytest]
DJANGO_SETTINGS_MODULE = rapidapipractice.settings

Fixtures

Number of useful fixtures are provided by pytest-django.

In-Memory SQLite

We define all fixtures in conftest.py. In this module we also update Django settings to use in-memory SQLite database:

from rapidapipractice import settings

settings.DATABASES['default'] = {
        'ENGINE': 'django.db.backends.sqlite3',
        'NAME': ':memory:',
    }

Initialize test database (`test_db` fixture)

We will create a test_db fixture which initializes the database and creates a user (`username=ivang;email=[email protected]). We are going to use this user later in tests.

Add following to conftest.py

import pytest
from django.core import management

@pytest.fixture
def test_db():
    """
    Initialize the test database. Note that this fixture should be
    used with test-cases marked with @pytest.mark.django_db
    """
    fixture_data = {
        'users': [
            { 'username': 'ivang', 'email': '[email protected]'}
        ]
    }
    for user_info in fixture_data['users']:
        management.call_command('createsuperuser', verbosity=0, interactive=False,
                **user_info)
    yield fixture_data

The fixture returns fixture data so that it could be used in test cases.

Final `conftest.py`

import pytest
from django.core import management
from rapidapipractice import settings

settings.DATABASES['default'] = {
        'ENGINE': 'django.db.backends.sqlite3',
        'NAME': ':memory:',
    }


@pytest.fixture
def test_db():
    """
    Initialize the test database. Note that this fixture should be
    used with test-cases marked with @pytest.mark.django_db
    """
    fixture_data = {
        'users': [
            { 'username': 'ivang', 'email': '[email protected]'}
        ]
    }
    management.call_command('makemigrations', verbosity=0, interactive=False)
    management.call_command('migrate', verbosity=0, interactive=False)
    for user_info in fixture_data['users']:
        management.call_command('createsuperuser', verbosity=0, interactive=False,
                **user_info)
    yield fixture_data

Executing tests

$ pytest -vv --cov=rapidapipractice --cov=api --cov-report=term

Test Cases for Users API

We will place our Users API test cases in tests/test_users_api.py

First Test Case - Smoke Test

We will start with reading the API root url and confirming it returns OK http response.

Add following to tests/test_users_api.py

def test_can_read_api_root(client):
    response = client.get('/api/')
    assert response.status_code == 200

The client fixture is provided by pytest-django plugin.

Test Case: Read existing user

import pytest

@pytest.mark.django_db
def test_read_existing_user_returns_user_info(client, test_db):
    response = client.get('/api/users/1/')
    assert response.status_code == 200
    assert response.data['username'] == 'ivang'
    assert response.data['email'] == '[email protected]'

import pytest is necessary for the django_db mark. The django_db mark is provided by the pytest-django plugin. It causes the Django database to be initialized and migrated before calling the test case. For more info refer to pytest-django documentation.

Test Case: Read non-existent user

Add following to tests/test_users_api.py

@pytest.mark.django_db
def test_read_not_existing_user_returns_404(client, test_db):
    response = client.get('/api/users/101/')
    assert response.status_code == 404

To interact with Django application, we use the client fixture, provided by pytest-django.

Test Case: Get users returns empty list on empty database

@pytest.mark.django_db
def test_get_usrers_on_empty_db_returns_empty_list(client):
    response = client.get('/api/users/')
    assert response.status_code == 200
    assert isinstance(response.data['results'], list)
    assert [] == response.data['results']

Test Case: Get users returns a list of users

@pytest.mark.django_db
def test_get_usrers_returns_empty_list_of_users(client, test_db):
    response = client.get('/api/users/')
    assert response.status_code == 200
    assert isinstance(response.data['results'], list)
    assert 1 == len(response.data['results'])
    actual = response.data['results'][0]
    assert 'ivang' == actual['username']

Test Case: Put user creates a user

@pytest.mark.django_db
def test_put_user_creates_user(client, test_db):
    data = {
        'username':'bbeggins',
        'email': '[email protected]',
    }
    response = client.post('/api/users/', data=data)
    print(response.data)
    assert response.status_code == 201
    assert '/api/users/2/' in response.data['url']
    user_response = client.get('/api/users/2/')
    assert user_response.status_code == 200
    assert 'bbeggins' == user_response.data['username']

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