django-swagger-tester 2.0.0

Django test utility for validating Swagger documentation

Django Swagger Tester

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Documentation: https://django-swagger-tester.readthedocs.io

Repository: https://github.com/sondrelg/django-swagger-tester

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This package is a simple test utility for your Django Swagger documentation.

Its aim is to make it easy for developers to catch and correct documentation errors in their Swagger docs by comparing documented responses to actual API responses, or validating documented request bodies using actual input serializers.

Features

The package has three main features:

• Testing response documentation

• Testing input documentation

• and ensuring your docs comply with a single parameter naming standard (case type).

  Supported naming standards include camelCase, snake_case, kebab-case, and PascalCase.

Implementations

This package currently supports:

• Testing of dynamically rendered OpenAPI schemas using using drf_yasg

• Testing of any implementation which generates a static schema yaml or json file (e.g., like DRF)

If you’re using another method to generate your documentation and would like to use this package, feel free to add an issue, or create a PR. Adding a new implementation is as easy as adding the required logic needed to load the OpenAPI schema.

Installation

Install using pip:

pip install django-swagger-tester

Configuration

Settings

To use Django Swagger Settings in your project, you first need to add a django_swagger_tester to your installed apps.

INSTALLED_APPS = [
    ...
    'django_swagger_tester',
]

Secondly, you need to configure the SWAGGER_TESTER package settings in your settings.py:

from django_swagger_tester.loaders import StaticSchemaLoader
from django_swagger_tester.case_testers import is_camel_case

SWAGGER_TESTER = {
    'SCHEMA_LOADER': StaticSchemaLoader,
    'PATH': './static/openapi-schema.yml',
    'CASE_TESTER': is_camel_case,
    'CASE_PASSLIST': [],
    'CAMEL_CASE_PARSER': False,
}

Parameters

SCHEMA_LOADER

The loader class you use is dictated by how your OpenAPI schema is generated. If your schema is a static file, you should use the StaticSchemaLoader. If not, you should select the loader class that serves your implementation.

Loader classes can be imported from django_swagger_tester.loaders and currently include:

• StaticSchemaLoader

• DrfYasgSchemaLoader

Example:

from django_swagger_tester.loaders import DrfYasgSchemaLoader

SWAGGER_TESTER = {
    'SCHEMA_LOADER': DrfYasgSchemaLoader,
}

PATH

Path takes the file path of your OpenAPI schema file. this is only required if you’re using the StaticSchemaLoader loader class.

Example:

SWAGGER_TESTER = {
    'PATH': BASE_DIR / '/openapi-schema.yml',
}

CASE_TESTER

The callable passed for this input decide the naming standard you wish to enforce for your documentation.

There are currently four supported options:

• camel case

• snake case

• pascal case

• kebab case

• or you can pass None to skip case validation completely

Your OpenAPI schema will be tested to make sure all parameter names are correctly cased according to this preference. If you do not wish to enforce this check, you can specify None to skip this feature.

Example:

from django_swagger_tester.case_testers import is_camel_case

SWAGGER_TESTER = {
    'CASE_TESTER': is_camel_case,
}

Default: None

CASE_PASSLIST

List of string for ignoring exceptions from general case-testing. Say you’ve decided that all your responses should be camel cased, but you’ve already made IP a capitalized response key; you can the add the key to your CASE_PASSLIST to avoid this being flagged as an error in your tests.

Example:

from django_swagger_tester.case_testers import is_camel_case

SWAGGER_TESTER = {
    'CASE_PASSLIST': ['IP', 'DHCP'],
}

Default: []

CAMEL_CASE_PARSER

Should be set to True if you use djangorestframework-camel-case’s CamelCaseJSONParser or CamelCaseJSONRenderer for your API views.

Example:

SWAGGER_TESTER = {
    'CAMEL_CASE_PARSER': True,
}

Default: False

Response Validation

To make sure your API response matches your documented response, the validate_response function compares the two at each level of depth.

A pytest implementation might look like this:

from django_swagger_tester.testing import validate_response

def test_200_response_documentation(client):
    route = 'api/v1/test/1'
    response = client.get(route)
    assert response.status_code == 200
    assert response.json() == expected_response

    # test swagger documentation
    validate_response(response=response, method='GET', route=route)

A Django-test implementation might look like this:

from django_swagger_tester.testing import validate_response

class MyApiTest(APITestCase):

    path = '/api/v1/test/'

    def setUp(self) -> None:
        user, _ = User.objects.update_or_create(username='test_user')
        self.client.force_authenticate(user=user)

    def test_get_200(self) -> None:
        response = self.client.get(self.path, headers={'Content-Type': 'application/json'})
        expected_response = [...]

        self.assertEqual(response.status_code, 200)
        self.assertEqual(response.json(), expected_response)

        # test swagger documentation
        validate_response(response=response, method='GET', route=self.path)

It is also possible to test more than a single response at the time:

def test_post_endpoint_responses(client):
    # 201 - Resource created
    response = client.post(...)
    validate_response(response=response, method='POST', route='api/v1/test/')

    # 400 - Bad data
    response = client.post(...)
    validate_response(response=response, method='POST', route='api/v1/test/')

def test_get_endpoint_responses(client):
    # 200 - Fetch resource
    response = client.get(...)
    validate_response(response=response, method='GET', route='api/v1/test/<id>')

    # 404 - Bad ID
    response = client.get(...)
    validate_response(response=response, method='GET', route='api/v1/test/<bad id>')

Errors

When found, errors will be raised in the following format:

django_swagger_tester.exceptions.SwaggerDocumentationError: Item is misspecified:

Summary
-------------------------------------------------------------------------------------------

Error:      The following properties seem to be missing from your response body: length, width.

Expected:   {'name': 'Saab', 'color': 'Yellow', 'height': 'Medium height', 'width': 'Very wide', 'length': '2 meters'}
Received:   {'name': 'Saab', 'color': 'Yellow', 'height': 'Medium height'}

Hint:       Remove the key(s) from you Swagger docs, or include it in your API response.
Sequence:   init.list

-------------------------------------------------------------------------------------------

* If you need more details: set `verbose=True`

Expected describes the response data, and Received describes the schema. In this example, the response data is missing two attributes, height and width, documented in the OpenAPI schema indicating that either the response needs to include more data, or that the OpenAPI schema should be corrected.

Some errors will include hints to help you understand what actions to take, to rectify the error.

Finally, all errors will include a Sequence string indicating how the response tester has iterated through the orignal data structure, before finding an error.

Input Validation

To make sure your request body documentation is accurate, and will stay accurate, you can use endpoint serializers to validate your schema directly.

validate_input_serializer constructs an example representation of the documented request body, and passes it to the serializer it is given. This means it’s only useful if you use serializers for validating your incoming request data.

A Django test implementation of input validation for a whole project could be structured like this:

from django.test import SimpleTestCase
from django_swagger_tester.testing import validate_input_serializer

from api.serializers.validation.request_bodies import ...


class TestSwaggerInput(SimpleTestCase):
    endpoints = [
        {
            'api/v1/orders/': [
                ('POST', ValidatePostOrderBody),
                ('PUT', ValidatePutOrderBody),
                ('DELETE', ValidateDeleteOrderBody)
            ]
        },
        {
            'api/v1/orders/<id>/entries/': [
                ('POST', ValidatePostEntryBody),
                ('PUT', ValidatePutEntryBody),
                ('DELETE', ValidateEntryDeleteBody)
            ]
        },
    ]

    def test_swagger_input(self) -> None:
        """
        Verifies that the documented request bodies are valid.
        """
        for endpoint in self.endpoints:
            for route, values in endpoint.items():
                for method, serializer in values:
                    validate_input_serializer(serializer=serializer, method=method, route=route)