141 lines
4.8 KiB
Plaintext
141 lines
4.8 KiB
Plaintext
|
|
.. highlightlang:: python
|
|
|
|
.. _mysetup:
|
|
|
|
Mysetup pattern: application specific test fixtures
|
|
==========================================================
|
|
|
|
Here is a basic useful step-by-step example for managing and interacting
|
|
with application specific test setup. The goal is to have one place
|
|
where we have the glue and test support code for bootstrapping and
|
|
configuring application objects and allow test modules and test
|
|
functions to stay ignorant of involved details.
|
|
|
|
Step 1: Implementing the test/app-specific ``mysetup`` pattern
|
|
--------------------------------------------------------------
|
|
|
|
Let's write a simple test function using a ``mysetup`` funcarg::
|
|
|
|
# content of test_sample.py
|
|
def test_answer(mysetup):
|
|
app = mysetup.myapp()
|
|
answer = app.question()
|
|
assert answer == 42
|
|
|
|
To run this test py.test needs to find and call a factory to
|
|
obtain the required ``mysetup`` function argument. To make
|
|
an according factory findable we write down a specifically named factory
|
|
method in a :ref:`local plugin <localplugin>` ::
|
|
|
|
# content of conftest.py
|
|
from myapp import MyApp
|
|
|
|
def pytest_funcarg__mysetup(request): # "mysetup" factory function
|
|
return MySetup()
|
|
|
|
class MySetup: # instances of this are seen by test functions
|
|
def myapp(self):
|
|
return MyApp()
|
|
|
|
To run the example we stub out a simple ``MyApp`` application object::
|
|
|
|
# content of myapp.py
|
|
class MyApp:
|
|
def question(self):
|
|
return 6 * 9
|
|
|
|
You can now run the test::
|
|
|
|
$ py.test test_sample.py
|
|
=========================== test session starts ============================
|
|
platform linux2 -- Python 2.7.1 -- pytest-2.2.4
|
|
collecting ... collected 1 items
|
|
|
|
test_sample.py F
|
|
|
|
================================= FAILURES =================================
|
|
_______________________________ test_answer ________________________________
|
|
|
|
mysetup = <conftest.MySetup instance at 0x17f21b8>
|
|
|
|
def test_answer(mysetup):
|
|
app = mysetup.myapp()
|
|
answer = app.question()
|
|
> assert answer == 42
|
|
E assert 54 == 42
|
|
|
|
test_sample.py:4: AssertionError
|
|
========================= 1 failed in 0.01 seconds =========================
|
|
|
|
This means that our ``mysetup`` object was successfully instantiated
|
|
and ``mysetup.app()`` returned an initialized ``MyApp`` instance.
|
|
We can ask it about the question and if you are confused as to what
|
|
the concrete question or answers actually mean, please see here_.
|
|
|
|
.. _here: http://uncyclopedia.wikia.com/wiki/The_Hitchhiker's_Guide_to_the_Galaxy
|
|
.. _`tut-cmdlineoption`:
|
|
|
|
Step 2: Checking a command line option and skipping tests
|
|
-----------------------------------------------------------
|
|
|
|
To add a command line option we update the ``conftest.py`` of
|
|
the previous example to add a command line option
|
|
and to offer a new mysetup method::
|
|
|
|
# content of ./conftest.py
|
|
import pytest
|
|
from myapp import MyApp
|
|
|
|
def pytest_funcarg__mysetup(request): # "mysetup" factory function
|
|
return MySetup(request)
|
|
|
|
def pytest_addoption(parser):
|
|
parser.addoption("--ssh", action="store", default=None,
|
|
help="specify ssh host to run tests with")
|
|
|
|
|
|
class MySetup:
|
|
def __init__(self, request):
|
|
self.config = request.config
|
|
|
|
def myapp(self):
|
|
return MyApp()
|
|
|
|
def getsshconnection(self):
|
|
host = self.config.option.ssh
|
|
if host is None:
|
|
pytest.skip("specify ssh host with --ssh")
|
|
return execnet.SshGateway(host)
|
|
|
|
|
|
Now any test function can use the ``mysetup.getsshconnection()`` method
|
|
like this::
|
|
|
|
# content of test_ssh.py
|
|
class TestClass:
|
|
def test_function(self, mysetup):
|
|
conn = mysetup.getsshconnection()
|
|
# work with conn
|
|
|
|
Running it yields::
|
|
|
|
$ py.test test_ssh.py -rs
|
|
=========================== test session starts ============================
|
|
platform linux2 -- Python 2.7.1 -- pytest-2.2.4
|
|
collecting ... collected 1 items
|
|
|
|
test_ssh.py s
|
|
========================= short test summary info ==========================
|
|
SKIP [1] /tmp/doc-exec-220/conftest.py:22: specify ssh host with --ssh
|
|
|
|
======================== 1 skipped in 0.01 seconds =========================
|
|
|
|
If you specify a command line option like ``py.test --ssh=python.org`` the test will execute as expected.
|
|
|
|
Note that neither the ``TestClass`` nor the ``test_function`` need to
|
|
know anything about how to setup the test state. It is handled separately
|
|
in your "test setup glue" code in the ``conftest.py`` file. It is easy
|
|
to extend the ``mysetup`` object for further needs in the test code - and for use by any other test functions in the files and directories below the ``conftest.py`` file.
|
|
|