implement pytest.mark.usefixtures and ini-file usefixtures setting

and also refine fixture docs a bit - fixtures.txt should now mostly
reflect the current state of the implementation
This commit is contained in:
holger krekel 2012-10-05 19:20:40 +02:00
parent 4cbb2ab3b3
commit d8c365ef2c
5 changed files with 192 additions and 107 deletions

View File

@ -77,6 +77,8 @@ def pytest_addoption(parser):
group.addoption('--fixtures', '--fixtures',
action="store_true", dest="showfixtures", default=False,
help="show available fixtures, sorted by plugin appearance")
parser.addini("usefixtures", type="args", default=(),
help="list of default fixtures to be used with this project")
parser.addini("python_files", type="args",
default=('test_*.py', '*_test.py'),
help="glob-style file patterns for Python test module discovery")
@ -879,7 +881,6 @@ class Function(FunctionMixin, pytest.Item, FuncargnamesCompatAttr):
#req._discoverfactories()
if callobj is not _dummy:
self.obj = callobj
self.fixturenames = self._getfuncargnames()
for name, val in (py.builtin._getfuncdict(self.obj) or {}).items():
setattr(self.markers, name, val)
@ -887,11 +888,17 @@ class Function(FunctionMixin, pytest.Item, FuncargnamesCompatAttr):
for name, val in keywords.items():
setattr(self.markers, name, val)
# contstruct a list of all neccessary fixtures for this test function
if hasattr(self.markers, "usefixtures"):
usefixtures = list(self.markers.usefixtures.args)
else:
usefixtures = []
self.fixturenames = (self.session._fixturemanager.getdefaultfixtures() +
usefixtures + self._getfuncargnames())
def _getfuncargnames(self):
startindex = int(self.cls is not None)
return (self.session._fixturemanager._autofixtures +
getfuncargnames(self.obj, startindex=startindex))
return getfuncargnames(self.obj, startindex=startindex)
@property
def function(self):
@ -1336,8 +1343,22 @@ class FixtureManager:
for plugin in plugins:
self.pytest_plugin_registered(plugin)
def getdefaultfixtures(self):
""" return a list of default fixture names (XXX for the given file path). """
try:
return self._defaultfixtures
except AttributeError:
defaultfixtures = list(self.config.getini("usefixtures"))
# make sure the self._autofixtures list is sorted
# by scope, scopenum 0 is session
self._autofixtures.sort(
key=lambda x: self.arg2fixturedeflist[x][-1].scopenum)
defaultfixtures.extend(self._autofixtures)
self._defaultfixtures = defaultfixtures
return defaultfixtures
def getfixtureclosure(self, fixturenames, parentnode):
# collect the closure of all funcargs, starting with the given
# collect the closure of all fixtures , starting with the given
# fixturenames as the initial set. As we have to visit all
# factory definitions anyway, we also return a arg2fixturedeflist
# mapping so that the caller can reuse it and does not have
@ -1345,7 +1366,7 @@ class FixtureManager:
# (discovering matching fixtures for a given name/node is expensive)
parentid = parentnode.nodeid
fixturenames_closure = list(self._autofixtures)
fixturenames_closure = list(self.getdefaultfixtures())
def merge(otherlist):
for arg in otherlist:
if arg not in fixturenames_closure:
@ -1434,11 +1455,11 @@ class FixtureManager:
faclist = self.arg2fixturedeflist.setdefault(name, [])
faclist.append(fixturedef)
if marker.autoactive:
# make sure the self._autofixtures list is always sorted
# by scope, scopenum 0 is session
self._autofixtures.append(name)
self._autofixtures.sort(
key=lambda x: self.arg2fixturedeflist[x][-1].scopenum)
try:
del self._defaultfixtures
except AttributeError:
pass
def getfixturedeflist(self, argname, nodeid):
try:

View File

@ -53,7 +53,7 @@ class TestCaseFunction(pytest.Function):
_excinfo = None
def _getfuncargnames(self):
return list(self.session._fixturemanager._autofixtures)
return []
def setup(self):
self._testcase = self.parent.obj(self.name)

View File

@ -17,7 +17,7 @@
#
# The full version, including alpha/beta/rc tags.
# The short X.Y version.
version = release = "2.3.0.dev9"
version = release = "2.3.0.dev18"
import sys, os

View File

@ -18,50 +18,54 @@ pytest fixtures: modular, re-useable, flexible
.. _`pytest-django`: https://pypi.python.org/pytest-django
.. _`Dependency injection`: http://en.wikipedia.org/wiki/Dependency_injection#Definition
pytest allows to provide and use test fixtures in a modular and flexible
manner, offering major improvements over the classic xUnit style of
pytest allows to create and use test fixtures in a modular and flexible
manner, offering dramatic improvements over the classic xUnit style of
setup/teardown functions. The `general purpose of test fixtures`_ is to
provide a fixed baseline upon which tests can reliably and
repeatedly execute. With pytest, fixtures are implemented by
**fixture functions** which may return a fixture object, put extra
attributes on test classes or perform side effects. The name of a
fixture function is significant and is used for invoking or activating it.
repeatedly execute. With pytest, fixtures have names and can be referenced
from test functions, modules, classes or whole projects. Fixtures are
implemented by **fixture functions** which may return a fixture object
or put extra attributes on test classes or perform global side effects
if needed. Fixtures can themselves access other fixtures, allowing a
**structured modular approach** to organising fixtures for an
application.
**Test functions can receive fixture objects by naming them as an input
argument.** For each argument name, a matching fixture
function will provide a fixture object. This mechanism has been
function will provide a fixture object. This mechanism was already
introduced with pytest-2.0 and is also called the **funcarg mechanism**.
It allows test functions to easily receive and work against specific
pre-initialized application objects without having to care about the
details of setup/cleanup procedures. This mechanism is a prime example of
details of setup/cleanup procedures. It's a prime example of
`dependency injection`_ where fixture functions take the role of the
*injector* and test functions are the *consumers* of fixture objects.
With pytest-2.3 this mechanism has been much improved to help with
sharing and parametrizing fixtures across test runs.
With pytest-2.3 this mechanism has been generalized and improved as described
further in this document.
**Test classes, modules or whole projects can declare a need for
one or more fixtures**. All required fixture functions will execute
before a test from the specifying context executes. They will
typically not provide a fixture object but rather perform side effects
like reading or preparing default config settings and pre-initializing
an application. For example, the Django_ project requires database
before a test from the specifying context executes. You can use this
to make tests operate from a pre-initialized directory or with
certain environment variables or with pre-initialized applications.
For example, the Django_ project requires database
initialization to be able to import from and use its model objects.
Plugins like `pytest-django`_ provide baseline fixtures which your
project can then easily depend or extend on.
For that, the `pytest-django`_ plugin provides fixtures which your
project can then easily depend or extend on, simply by referencing the
name of the particular fixture.
**Fixtures can be shared throughout a test session, module or class.**.
By means of a "scope" declaration on a fixture function, it will
only be invoked once per the specified scope. Sharing expensive application
object setups between tests typically helps to speed up test runs.
only be invoked once per the specified scope. This allows to reduce the number
of expensive application object setups and thus helps to speed up test runs.
Typical examples are the setup of test databases or establishing
required subprocesses or network connections.
**Fixture functions have controlled visilibity** which depends on where they
**Fixture functions have limited visilibity** which depends on where they
are defined. If they are defined on a test class, only its test methods
may use it. A fixture defined in a module can only be used
from that test module. A fixture defined in a conftest.py file
can only be used by the tests below the directory of that file.
Lastly plugins can define fixtures which are available across all
Lastly, plugins can define fixtures which are available across all
projects.
**Fixture functions can interact with the requesting testcontext**. By
@ -70,17 +74,17 @@ the function, class or module for which they are invoked and can
optionally register cleanup functions which are called when the last
test finished execution. A good example is `pytest-timeout`_ which
allows to limit the execution time of a test, and will read the
according parameter from a test function or from project-wide setting.
according parameter from a test function or from project-wide settings.
**Fixture functions can be parametrized** in which case they will be called
multiple times, each time executing the set of dependent tests, i. e. the
tests that depend on this fixture. Test functions do usually not need
to be aware of their re-running. Fixture parametrization helps to
write functional tests for components which themselves can be
write exhaustive functional tests for components which themselves can be
configured in multiple ways.
Basic funcarg fixture example
Basic test function with fixtures
-----------------------------------------------------------
.. versionadded:: 2.3
@ -92,21 +96,22 @@ visible fixture function and a test function using the provided fixture::
# content of ./test_simplefactory.py
import pytest
@pytest.fixture
@pytest.fixture()
def myfuncarg():
return 42
def test_function(myfuncarg):
assert myfuncarg == 17
Here, the ``test_function`` needs an object named ``myfuncarg`` and thus
py.test will discover and call the ``@pytest.fixture`` marked ``myfuncarg``
factory function. Running the tests looks like this::
Here, the ``test_function`` needs a very simple fixture ``myfuncarg`` which
it wants to compare against a specific value. py.test will discover and call
the ``@pytest.fixture`` marked ``myfuncarg`` fixture function. Running the
tests looks like this::
$ py.test test_simplefactory.py
=========================== test session starts ============================
platform linux2 -- Python 2.7.3 -- pytest-2.3.0.dev11
plugins: xdist, bugzilla, cache, oejskit, cli, timeout, pep8, cov
platform linux2 -- Python 2.7.3 -- pytest-2.3.0.dev18
plugins: xdist, bugzilla, cache, oejskit, cli, pep8, cov, timeout
collecting ... collected 1 items
test_simplefactory.py F
@ -129,7 +134,7 @@ how py.test comes to call the test function this way:
1. py.test :ref:`finds <test discovery>` the ``test_function`` because
of the ``test_`` prefix. The test function needs a function argument
named ``myfuncarg``. A matching factory function is discovered by
named ``myfuncarg``. A matching fixture function is discovered by
looking for a fixture function named ``myfuncarg``.
2. ``myfuncarg()`` is called to create a value ``42``.
@ -150,7 +155,7 @@ with a list of available function arguments.
to see available fixtures.
In versions prior to 2.3 there was no @pytest.fixture marker
and you had to instead use a magic ``pytest_funcarg__NAME`` prefix
and you had to use a magic ``pytest_funcarg__NAME`` prefix
for the fixture factory. This remains and will remain supported
but is not advertised as the primary means of declaring fixture
functions.
@ -163,7 +168,7 @@ Creating and using a session-shared fixture
Here is a simple example of a fixture function creating a shared
``smtplib.SMTP`` connection fixture which test functions from
test modules below the directory of a ``conftest.py`` file may use::
any test module inside the directory of a ``conftest.py`` file may use::
# content of conftest.py
import pytest
@ -178,6 +183,7 @@ listing the name ``smtp`` as an input parameter in any test or setup
function::
# content of test_module.py
def test_ehlo(smtp):
response = smtp.ehlo()
assert response[0] == 250
@ -198,7 +204,7 @@ inspect what is going on and can now run the tests::
================================= FAILURES =================================
________________________________ test_ehlo _________________________________
smtp = <smtplib.SMTP instance at 0x31bce18>
smtp = <smtplib.SMTP instance at 0x2c64128>
def test_ehlo(smtp):
response = smtp.ehlo()
@ -210,7 +216,7 @@ inspect what is going on and can now run the tests::
test_module.py:5: AssertionError
________________________________ test_noop _________________________________
smtp = <smtplib.SMTP instance at 0x31bce18>
smtp = <smtplib.SMTP instance at 0x2c64128>
def test_noop(smtp):
response = smtp.noop()
@ -219,19 +225,23 @@ inspect what is going on and can now run the tests::
E assert 0
test_module.py:10: AssertionError
2 failed in 0.26 seconds
2 failed in 0.15 seconds
you see the two ``assert 0`` failing and can also see that
the same (session-scoped) object was passed into the two test functions
because pytest shows the incoming arguments in the traceback.
Adding a finalizer to a fixture
--------------------------------------------------------
Further extending the ``smtp`` example, we now want to properly
close a smtp server connection after the last test using it
has been run. We can do this by calling the ``request.addfinalizer()``
helper::
has been run. We can do this by changing the fixture function
to accept the special :ref:`request` object, representing the
requesting test context. After calling the ``request.addfinalizer()``
helper pytest will make sure that the finalizer function is called
after the last test using the ``smtp`` resource has finished.
# content of conftest.py
import pytest
@ -250,10 +260,10 @@ The registered ``fin`` function will be called when the last test
using it has executed::
$ py.test -s -q --tb=no
collecting ... collected 4 items
FFFF
4 failed in 6.40 seconds
finalizing <smtplib.SMTP instance at 0x125d3b0>
collecting ... collected 2 items
FF
2 failed in 0.21 seconds
finalizing <smtplib.SMTP instance at 0x29f7908>
We see that the ``smtp`` instance is finalized after all
tests executed. If we had specified ``scope='function'``
@ -293,7 +303,7 @@ So let's just do another run::
================================= FAILURES =================================
__________________________ test_ehlo[merlinux.eu] __________________________
smtp = <smtplib.SMTP instance at 0x28dc5a8>
smtp = <smtplib.SMTP instance at 0x1c261b8>
def test_ehlo(smtp):
response = smtp.ehlo()
@ -305,7 +315,7 @@ So let's just do another run::
test_module.py:5: AssertionError
__________________________ test_noop[merlinux.eu] __________________________
smtp = <smtplib.SMTP instance at 0x28dc5a8>
smtp = <smtplib.SMTP instance at 0x1c261b8>
def test_noop(smtp):
response = smtp.noop()
@ -316,7 +326,7 @@ So let's just do another run::
test_module.py:10: AssertionError
________________________ test_ehlo[mail.python.org] ________________________
smtp = <smtplib.SMTP instance at 0x28e3e18>
smtp = <smtplib.SMTP instance at 0x1c2a4d0>
def test_ehlo(smtp):
response = smtp.ehlo()
@ -327,7 +337,7 @@ So let's just do another run::
test_module.py:4: AssertionError
________________________ test_noop[mail.python.org] ________________________
smtp = <smtplib.SMTP instance at 0x28e3e18>
smtp = <smtplib.SMTP instance at 0x1c2a4d0>
def test_noop(smtp):
response = smtp.noop()
@ -336,7 +346,7 @@ So let's just do another run::
E assert 0
test_module.py:10: AssertionError
4 failed in 6.17 seconds
4 failed in 6.62 seconds
We now get four failures because we are running the two tests twice with
different ``smtp`` fixture instances. Note that with the
@ -352,8 +362,8 @@ You can also look at the tests which pytest collects without running them::
$ py.test --collectonly
=========================== test session starts ============================
platform linux2 -- Python 2.7.3 -- pytest-2.3.0.dev11
plugins: xdist, bugzilla, cache, oejskit, cli, timeout, pep8, cov
platform linux2 -- Python 2.7.3 -- pytest-2.3.0.dev18
plugins: xdist, bugzilla, cache, oejskit, cli, pep8, cov, timeout
collecting ... collected 4 items
<Module 'test_module.py'>
<Function 'test_ehlo[merlinux.eu]'>
@ -400,15 +410,15 @@ Here we declare an ``app`` fixture which receives the previously defined
$ py.test -v test_appsetup.py
=========================== test session starts ============================
platform linux2 -- Python 2.7.3 -- pytest-2.3.0.dev11 -- /home/hpk/venv/1/bin/python
cachedir: /home/hpk/tmp/doc-exec-423/.cache
plugins: xdist, bugzilla, cache, oejskit, cli, timeout, pep8, cov
platform linux2 -- Python 2.7.3 -- pytest-2.3.0.dev18 -- /home/hpk/venv/1/bin/python
cachedir: /tmp/doc-exec-6/.cache
plugins: xdist, bugzilla, cache, oejskit, cli, pep8, cov, timeout
collecting ... collected 2 items
test_appsetup.py:12: test_exists[merlinux.eu] PASSED
test_appsetup.py:12: test_exists[mail.python.org] PASSED
test_appsetup.py:12: test_smtp_exists[merlinux.eu] PASSED
test_appsetup.py:12: test_smtp_exists[mail.python.org] PASSED
========================= 2 passed in 6.82 seconds =========================
========================= 2 passed in 0.14 seconds =========================
Due to the parametrization of ``smtp`` the test will run twice with two
different ``App`` instances and respective smtp servers. There is no
@ -463,9 +473,9 @@ Let's run the tests in verbose mode and with looking at the print-output::
$ py.test -v -s test_module.py
=========================== test session starts ============================
platform linux2 -- Python 2.7.3 -- pytest-2.3.0.dev11 -- /home/hpk/venv/1/bin/python
cachedir: /home/hpk/tmp/doc-exec-423/.cache
plugins: xdist, bugzilla, cache, oejskit, cli, timeout, pep8, cov
platform linux2 -- Python 2.7.3 -- pytest-2.3.0.dev18 -- /home/hpk/venv/1/bin/python
cachedir: /tmp/doc-exec-6/.cache
plugins: xdist, bugzilla, cache, oejskit, cli, pep8, cov, timeout
collecting ... collected 8 items
test_module.py:16: test_0[1] PASSED
@ -525,7 +535,7 @@ and declare its use in a test module via a ``needs`` marker::
import os
import pytest
@pytest.mark.needsfixtures("cleandir")
@pytest.mark.usefixtures("cleandir")
class TestDirectoryInit:
def test_cwd_starts_empty(self):
assert os.listdir(os.getcwd()) == []
@ -535,24 +545,24 @@ and declare its use in a test module via a ``needs`` marker::
def test_cwd_again_starts_empty(self):
assert os.listdir(os.getcwd()) == []
Due to the ``needs`` class marker, the ``cleandir`` fixture
Due to the ``usefixtures`` marker, the ``cleandir`` fixture
will be required for the execution of each of the test methods, just as if
you specified a "cleandir" function argument to each of them. Let's run it
to verify our fixture is activated::
$ py.test -q
collecting ... collected 2 items
.
2 passed in 0.01 seconds
..
2 passed in 0.02 seconds
You may specify the need for multiple fixtures::
@pytest.mark.needsfixtures("cleandir", "anotherfixture")
@pytest.mark.usefixtures("cleandir", "anotherfixture")
and you may specify fixture needs at the test module level, using
a generic feature of the mark mechanism::
pytestmark = pytest.mark.needsfixtures("cleandir")
pytestmark = pytest.mark.usefixtures("cleandir")
Lastly you can put fixtures required by all tests in your project
into an ini-file::
@ -560,20 +570,20 @@ into an ini-file::
# content of pytest.ini
[pytest]
needsfixtures = cleandir
usefixtures = cleandir
Implicit fixtures at class/module/directory/global level
autoactive fixtures at class/module/directory/global level
----------------------------------------------------------------------
.. regendoc:wipe
Occasionally, you may want to have fixtures get invoked automatically
without any ``needs`` reference. Also, if you are used to the classical
xUnit setup/teardown functions you may have gotten used to fixture
functions executing always. As a practical example,
without any ``usefixtures`` or funcargs reference. As a practical example,
suppose we have a database fixture which has a begin/rollback/commit
architecture and we want to surround each test method by a transaction
and a rollback. Here is a dummy self-contained implementation::
architecture and we want to automatically surround each test method by a
transaction and a rollback. Here is a dummy self-contained implementation
of this idea::
# content of test_db_transact.py
@ -582,46 +592,55 @@ and a rollback. Here is a dummy self-contained implementation::
@pytest.fixture(scope="module")
class db:
def __init__(self):
self.intransaction = False
def begin(self):
self.intransaction = True
def rollback(Self):
self.intransaction = False
self.intransaction = []
def begin(self, name):
self.intransaction.append(name)
def rollback(self):
self.intransaction.pop()
class TestClass:
@pytest.fixture(auto=True)
@pytest.fixture(autoactive=True)
def transact(self, request, db):
db.begin()
db.begin(request.function.__name__)
request.addfinalizer(db.rollback)
def test_method1(self, db):
assert db.intransaction
assert db.intransaction == ["test_method1"]
def test_method2(self):
pass
def test_method2(self, db):
assert db.intransaction == ["test_method2"]
The class-level ``transact`` fixture is marked with *auto=true* which will
mark all test methods in the class as needing the fixture.
The class-level ``transact`` fixture is marked with *autoactive=true* which implies
that all test methods in the class will use this fixture without a need to
specify it.
Here is how this maps to module, project and cross-project scopes:
If we run it, we get two passing tests::
- if an automatic fixture was defined in a test module, all its test
functions would automatically invoke it.
$ py.test -q
collecting ... collected 2 items
..
2 passed in 0.02 seconds
- if defined in a conftest.py file then all tests in all test
modules belows its directory will invoke the fixture.
And here is how autoactive fixtures work in other scopes:
- lastly, and **please use that with care**: if you define an automatic
- if an autoactive fixture is defined in a test module, all its test
functions automatically use it.
- if an autoactive fixture is defined in a conftest.py file then all tests in
all test modules belows its directory will invoke the fixture.
- lastly, and **please use that with care**: if you define an autoactive
fixture in a plugin, it will be invoked for all tests in all projects
where the plugin is installed. This can be useful if a fixture only
anyway works in the presence of certain settings in the ini-file. Such
a global fixture should thus quickly determine if it should do
anyway works in the presence of certain settings e. g. in the ini-file. Such
a global fixture should always quickly determine if it should do
any work and avoid expensive imports or computation otherwise.
Note that the above ``transact`` fixture may very well be something that
you want to make available in your project without having each test function
in your project automatically using it. The canonical way to do that is to put
the transact definition into a conftest.py file without using ``auto``::
you want to make available in your project but which requires an explicit using
reference to have it activated. The canonical way to do that is to put
the transact definition into a conftest.py file without using
``autoactive``::
# content of conftest.py
@pytest.fixture()
@ -631,13 +650,13 @@ the transact definition into a conftest.py file without using ``auto``::
and then have a TestClass using it by declaring the need::
@pytest.mark.needsfixtures("transact")
@pytest.mark.usefixtures("transact")
class TestClass:
def test_method1(self):
...
While all test methods in this TestClass will thus use the transaction
fixture, other test classes will not unless they state the need.
While all test methods in this TestClass will use the transaction
fixture, other test classes or function will not do so without a marker or funcarg.
.. currentmodule:: _pytest.python

View File

@ -1791,6 +1791,51 @@ class TestFixtureFactory:
reprec = testdir.inline_run()
reprec.assertoutcome(passed=1)
def test_usefixtures_marker(self, testdir):
testdir.makepyfile("""
import pytest
l = []
@pytest.fixture(scope="class")
def myfix(request):
request.cls.hello = "world"
l.append(1)
class TestClass:
def test_one(self):
assert self.hello == "world"
assert len(l) == 1
def test_two(self):
assert self.hello == "world"
assert len(l) == 1
pytest.mark.usefixtures("myfix")(TestClass)
""")
reprec = testdir.inline_run()
reprec.assertoutcome(passed=2)
def test_usefixtures_ini(self, testdir):
testdir.makeini("""
[pytest]
usefixtures = myfix
""")
testdir.makeconftest("""
import pytest
@pytest.fixture(scope="class")
def myfix(request):
request.cls.hello = "world"
""")
testdir.makepyfile("""
class TestClass:
def test_one(self):
assert self.hello == "world"
def test_two(self):
assert self.hello == "world"
""")
reprec = testdir.inline_run()
reprec.assertoutcome(passed=2)
class TestResourceIntegrationFunctional:
def test_parametrize_with_ids(self, testdir):