WebTest

3.0.7 · active · verified Sat Apr 11

WebTest is a Python library that wraps any WSGI application, making it easy to send test requests without starting an HTTP server. It provides convenient full-stack testing for WSGI-compatible frameworks. An extraction of `paste.fixture.TestApp`, rewritten to use `WebOb`, it is under active development as part of the Pylons cloud of packages and is currently at version 3.0.7.

Warnings

breaking Version 3.0.0 dropped support for Python 2.7 and Python 3.5. Applications must use Python 3.6+ (3.9+ officially supported).
Fix: Upgrade Python environment to 3.6 or newer (preferably 3.9+). Review code for Python 2/3.5 specific syntax.
breaking Version 2.0 introduced several breaking changes, including the removal of `anchor` from `TestResponse.click` and `button` from `TestResponse.clickbutton`. The cookiejar API changed for Python 3.3. Selenium and CasperJS integrations were moved to separate, optional packages (`webtest-selenium`, `webtest-casperjs`).
Fix: Update usage of `click` methods, adapt to the new cookiejar API if targeting Python 3.3+, and install `webtest-selenium` or `webtest-casperjs` if those integrations are still required.
gotcha By default, `TestApp.get()`, `post()`, and other request methods raise an `AppError` if the response status code is not 2xx or 3xx (success or redirect).
Fix: If expecting an error status (e.g., 404, 500), pass `status=EXPECTED_STATUS_CODE` (e.g., `status=404`) or `expect_errors=True` to the request method (e.g., `app.get('/nonexistent', status=404)` or `app.post('/error', expect_errors=True)`).
gotcha Accessing parsed response attributes like `resp.html`, `resp.xml`, `resp.lxml`, `resp.pyquery`, or `resp.json` requires the respective parsing library (BeautifulSoup4, lxml, PyQuery, or `json` module for `json`) to be installed. An `ImportError` or `AttributeError` may be raised if the library is missing or the content-type is incorrect.
Fix: Ensure the necessary parsing library is installed (`pip install beautifulsoup4 lxml pyquery`) and that the response's `Content-Type` header matches the expected format (e.g., `text/html` for `.html`, `application/json` for `.json`).

Install

pip install WebTest Install stable version

Imports

TestApp
```
from webtest import TestApp
```
While `webtest.app.TestApp` works, the idiomatic and stable import is directly from the `webtest` package.

Quickstart

Initializes `TestApp` with a basic WSGI application and performs a GET request, asserting the response status and content.

from webtest import TestApp

def simple_app(environ, start_response):
    status = '200 OK'
    headers = [('Content-type', 'text/plain')]
    start_response(status, headers)
    return [b'Hello, world!']

app = TestApp(simple_app)
resp = app.get('/')

assert resp.status == '200 OK'
assert 'Hello, world!' in resp.text

print(f"Status: {resp.status}")
print(f"Body: {resp.text}")

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