mirror of https://github.com/mitsuhiko/flask.git
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
116 lines
3.9 KiB
116 lines
3.9 KiB
.. _testing: |
|
|
|
Testing Flask Applications |
|
========================== |
|
|
|
**Something that is untested is broken.** |
|
|
|
Not sure where that is coming from, and it's not entirely correct, but |
|
also not that far from the truth. Untested applications make it hard to |
|
improve existing code and developers of untested applications tend to |
|
become pretty paranoid. If an application however has automated tests you |
|
can savely change things and you will instantly know if your change broke |
|
something. |
|
|
|
Flask gives you a couple of ways to test applications. It mainly does |
|
that by exposing the Werkzeug test :class:`~werkzeug.Client` class to your |
|
code and handling the context locals for you. You can then use that with |
|
your favourite testing solution. In this documentation we will us the |
|
:mod:`unittest` package that comes preinstalled with each Python |
|
installation. |
|
|
|
The Application |
|
--------------- |
|
|
|
First we need an application to test for functionality. Let's start |
|
simple with a Hello World application (`hello.py`):: |
|
|
|
from flask import Flask, render_template_string |
|
app = Flask(__name__) |
|
|
|
@app.route('/') |
|
@app.route('/<name>') |
|
def hello(name='World'): |
|
return render_template_string(''' |
|
<!doctype html> |
|
<title>Hello {{ name }}!</title> |
|
<h1>Hello {{ name }}!</h1> |
|
''', name=name) |
|
|
|
The Testing Skeleton |
|
-------------------- |
|
|
|
In order to test that, we add a second module ( |
|
`hello_tests.py`) and create a unittest skeleton there:: |
|
|
|
import unittest |
|
import hello |
|
|
|
class HelloWorldTestCase(unittest.TestCase): |
|
|
|
def setUp(self): |
|
self.app = hello.app.test_client() |
|
|
|
if __name__ == '__main__': |
|
unittest.main() |
|
|
|
The code in the `setUp` function creates a new test client. That function |
|
is called before each individual test function. What the test client does |
|
for us is giving us a simple interface to the application. We can trigger |
|
test requests to the application and the client will also keep track of |
|
cookies for us. |
|
|
|
If we now run that testsuite, we should see the following output:: |
|
|
|
$ python hello_tests.py |
|
|
|
---------------------------------------------------------------------- |
|
Ran 0 tests in 0.000s |
|
|
|
OK |
|
|
|
Even though it did not run any tests, we already know that our hello |
|
application is syntactically valid, otherwise the import would have died |
|
with an exception. |
|
|
|
The First Test |
|
-------------- |
|
|
|
Now we can add the first test. Let's check that the application greets us |
|
with "Hello World" if we access it on ``/``. For that we modify our |
|
created test case class so that it looks like this:: |
|
|
|
class HelloWorldTestCase(unittest.TestCase): |
|
|
|
def setUp(self): |
|
self.app = hello.app.test_client() |
|
|
|
def test_hello_world(self): |
|
rv = self.app.get('/') |
|
assert 'Hello World!' in rv.data |
|
|
|
Test functions begin with the word `test`. Every function named like that |
|
will be picked up automatically. By using `self.app.get` we can send an |
|
HTTP `GET` request to the application with the given path. The return |
|
value will be a :class:`~flask.Flask.response_class` object. We can now |
|
use the :attr:`~werkzeug.BaseResponse.data` attribute to inspect the |
|
return value (as string) from the application. In this case, we ensure |
|
that ``'Hello World!'`` is part of the output. |
|
|
|
Run it again and you should see one passing test. Let's add a second test |
|
here:: |
|
|
|
def test_hello_name(self): |
|
rv = self.app.get('/Peter') |
|
assert 'Hello Peter!' in rv.data |
|
|
|
Of course you can submit forms with the test client as well. For that and |
|
other features of the test client, check the documentation of the Werkzeug |
|
test :class:`~werkzeug.Client` and the tests of the MiniTwit example |
|
application: |
|
|
|
- Werkzeug Test :class:`~werkzeug.Client` |
|
- `MiniTwit Example`_ |
|
|
|
.. _MiniTwit Example: |
|
http://github.com/mitsuhiko/flask/tree/master/examples/minitwit/
|
|
|