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"""Attribute selector plugin.
Oftentimes when testing you will want to select tests based on
criteria rather then simply by filename. For example, you might want
to run all tests except for the slow ones. You can do this with the
Attribute selector plugin by setting attributes on your test methods.
Here is an example:
.. code-block:: python
def test_big_download():
import urllib
# commence slowness...
test_big_download.slow = 1
Once you've assigned an attribute ``slow = 1`` you can exclude that
test and all other tests having the slow attribute by running ::
$ nosetests -a '!slow'
There is also a decorator available for you that will set attributes.
Here's how to set ``slow=1`` like above with the decorator:
.. code-block:: python
from nose.plugins.attrib import attr
@attr('slow')
def test_big_download():
import urllib
# commence slowness...
And here's how to set an attribute with a specific value:
.. code-block:: python
from nose.plugins.attrib import attr
@attr(speed='slow')
def test_big_download():
import urllib
# commence slowness...
This test could be run with ::
$ nosetests -a speed=slow
In Python 2.6 and higher, ``@attr`` can be used on a class to set attributes
on all its test methods at once. For example:
.. code-block:: python
from nose.plugins.attrib import attr
@attr(speed='slow')
class MyTestCase:
def test_long_integration(self):
pass
def test_end_to_end_something(self):
pass
Below is a reference to the different syntaxes available.
Simple syntax
-------------
Examples of using the ``-a`` and ``--attr`` options:
* ``nosetests -a status=stable``
Only runs tests with attribute "status" having value "stable"
* ``nosetests -a priority=2,status=stable``
Runs tests having both attributes and values
* ``nosetests -a priority=2 -a slow``
Runs tests that match either attribute
* ``nosetests -a tags=http``
If a test's ``tags`` attribute was a list and it contained the value
``http`` then it would be run
* ``nosetests -a slow``
Runs tests with the attribute ``slow`` if its value does not equal False
(False, [], "", etc...)
* ``nosetests -a '!slow'``
Runs tests that do NOT have the attribute ``slow`` or have a ``slow``
attribute that is equal to False
**NOTE**:
if your shell (like bash) interprets '!' as a special character make sure to
put single quotes around it.
Expression Evaluation
---------------------
Examples using the ``-A`` and ``--eval-attr`` options:
* ``nosetests -A "not slow"``
Evaluates the Python expression "not slow" and runs the test if True
* ``nosetests -A "(priority > 5) and not slow"``
Evaluates a complex Python expression and runs the test if True
"""
import inspect
import logging
import os
import sys
from inspect import isfunction
from nose.plugins.base import Plugin
from nose.util import tolist
log = logging.getLogger('nose.plugins.attrib')
compat_24 = sys.version_info >= (2, 4)
def attr(*args, **kwargs):
"""Decorator that adds attributes to classes or functions
for use with the Attribute (-a) plugin.
"""
def wrap_ob(ob):
for name in args:
setattr(ob, name, True)
for name, value in kwargs.items():
setattr(ob, name, value)
return ob
return wrap_ob
def get_method_attr(method, cls, attr_name, default = False):
"""Look up an attribute on a method/ function.
If the attribute isn't found there, looking it up in the
method's class, if any.
"""
Missing = object()
value = getattr(method, attr_name, Missing)
if value is Missing and cls is not None:
value = getattr(cls, attr_name, Missing)
if value is Missing:
return default
return value
class ContextHelper:
"""Object that can act as context dictionary for eval and looks up
names as attributes on a method/ function and its class.
"""
def __init__(self, method, cls):
self.method = method
self.cls = cls
def __getitem__(self, name):
return get_method_attr(self.method, self.cls, name)
class AttributeSelector(Plugin):
"""Selects test cases to be run based on their attributes.
"""
def __init__(self):
Plugin.__init__(self)
self.attribs = []
def options(self, parser, env):
"""Register command line options"""
parser.add_option("-a", "--attr",
dest="attr", action="append",
default=env.get('NOSE_ATTR'),
metavar="ATTR",
help="Run only tests that have attributes "
"specified by ATTR [NOSE_ATTR]")
# disable in < 2.4: eval can't take needed args
if compat_24:
parser.add_option("-A", "--eval-attr",
dest="eval_attr", metavar="EXPR", action="append",
default=env.get('NOSE_EVAL_ATTR'),
help="Run only tests for whose attributes "
"the Python expression EXPR evaluates "
"to True [NOSE_EVAL_ATTR]")
def configure(self, options, config):
"""Configure the plugin and system, based on selected options.
attr and eval_attr may each be lists.
self.attribs will be a list of lists of tuples. In that list, each
list is a group of attributes, all of which must match for the rule to
match.
"""
self.attribs = []
# handle python eval-expression parameter
if compat_24 and options.eval_attr:
eval_attr = tolist(options.eval_attr)
for attr in eval_attr:
# "<python expression>"
# -> eval(expr) in attribute context must be True
def eval_in_context(expr, obj, cls):
return eval(expr, None, ContextHelper(obj, cls))
self.attribs.append([(attr, eval_in_context)])
# attribute requirements are a comma separated list of
# 'key=value' pairs
if options.attr:
std_attr = tolist(options.attr)
for attr in std_attr:
# all attributes within an attribute group must match
attr_group = []
for attrib in attr.strip().split(","):
# don't die on trailing comma
if not attrib:
continue
items = attrib.split("=", 1)
if len(items) > 1:
# "name=value"
# -> 'str(obj.name) == value' must be True
key, value = items
else:
key = items[0]
if key[0] == "!":
# "!name"
# 'bool(obj.name)' must be False
key = key[1:]
value = False
else:
# "name"
# -> 'bool(obj.name)' must be True
value = True
attr_group.append((key, value))
self.attribs.append(attr_group)
if self.attribs:
self.enabled = True
def validateAttrib(self, method, cls = None):
"""Verify whether a method has the required attributes
The method is considered a match if it matches all attributes
for any attribute group.
."""
# TODO: is there a need for case-sensitive value comparison?
any = False
for group in self.attribs:
match = True
for key, value in group:
attr = get_method_attr(method, cls, key)
if callable(value):
if not value(key, method, cls):
match = False
break
elif value is True:
# value must exist and be True
if not bool(attr):
match = False
break
elif value is False:
# value must not exist or be False
if bool(attr):
match = False
break
elif type(attr) in (list, tuple):
# value must be found in the list attribute
if not str(value).lower() in [str(x).lower()
for x in attr]:
match = False
break
else:
# value must match, convert to string and compare
if (value != attr
and str(value).lower() != str(attr).lower()):
match = False
break
any = any or match
if any:
# not True because we don't want to FORCE the selection of the
# item, only say that it is acceptable
return None
return False
def wantFunction(self, function):
"""Accept the function if its attributes match.
"""
return self.validateAttrib(function)
def wantMethod(self, method):
"""Accept the method if its attributes match.
"""
try:
cls = method.__self__.__class__
except AttributeError:
return False
return self.validateAttrib(method, cls)
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