# -*- coding: utf-8 -*- """Decorators for labeling test objects. Decorators that merely return a modified version of the original function object are straightforward. Decorators that return a new function object need to use nose.tools.make_decorator(original_function)(decorator) in returning the decorator, in order to preserve metadata such as function name, setup and teardown functions and so on - see nose.tools for more information. This module provides a set of useful decorators meant to be ready to use in your own tests. See the bottom of the file for the ready-made ones, and if you find yourself writing a new one that may be of generic use, add it here. Included decorators: Lightweight testing that remains unittest-compatible. - An @as_unittest decorator can be used to tag any normal parameter-less function as a unittest TestCase. Then, both nose and normal unittest will recognize it as such. This will make it easier to migrate away from Nose if we ever need/want to while maintaining very lightweight tests. NOTE: This file contains IPython-specific decorators. Using the machinery in IPython.external.decorators, we import either numpy.testing.decorators if numpy is available, OR use equivalent code in IPython.external._decorators, which we've copied verbatim from numpy. """ # Copyright (c) IPython Development Team. # Distributed under the terms of the Modified BSD License. import sys import os import tempfile import unittest import warnings from importlib import import_module from decorator import decorator # Expose the unittest-driven decorators from .ipunittest import ipdoctest, ipdocstring # Grab the numpy-specific decorators which we keep in a file that we # occasionally update from upstream: decorators.py is a copy of # numpy.testing.decorators, we expose all of it here. from IPython.external.decorators import * # For onlyif_cmd_exists decorator from IPython.utils.py3compat import string_types, which, PY2, PY3, PYPY #----------------------------------------------------------------------------- # Classes and functions #----------------------------------------------------------------------------- # Simple example of the basic idea def as_unittest(func): """Decorator to make a simple function into a normal test via unittest.""" class Tester(unittest.TestCase): def test(self): func() Tester.__name__ = func.__name__ return Tester # Utility functions def apply_wrapper(wrapper,func): """Apply a wrapper to a function for decoration. This mixes Michele Simionato's decorator tool with nose's make_decorator, to apply a wrapper in a decorator so that all nose attributes, as well as function signature and other properties, survive the decoration cleanly. This will ensure that wrapped functions can still be well introspected via IPython, for example. """ warnings.warn("The function `apply_wrapper` is deprecated and might be removed in IPython 5.0", DeprecationWarning) import nose.tools return decorator(wrapper,nose.tools.make_decorator(func)(wrapper)) def make_label_dec(label,ds=None): """Factory function to create a decorator that applies one or more labels. Parameters ---------- label : string or sequence One or more labels that will be applied by the decorator to the functions it decorates. Labels are attributes of the decorated function with their value set to True. ds : string An optional docstring for the resulting decorator. If not given, a default docstring is auto-generated. Returns ------- A decorator. Examples -------- A simple labeling decorator: >>> slow = make_label_dec('slow') >>> slow.__doc__ "Labels a test as 'slow'." And one that uses multiple labels and a custom docstring: >>> rare = make_label_dec(['slow','hard'], ... "Mix labels 'slow' and 'hard' for rare tests.") >>> rare.__doc__ "Mix labels 'slow' and 'hard' for rare tests." Now, let's test using this one: >>> @rare ... def f(): pass ... >>> >>> f.slow True >>> f.hard True """ warnings.warn("The function `make_label_dec` is deprecated and might be removed in IPython 5.0", DeprecationWarning) if isinstance(label, string_types): labels = [label] else: labels = label # Validate that the given label(s) are OK for use in setattr() by doing a # dry run on a dummy function. tmp = lambda : None for label in labels: setattr(tmp,label,True) # This is the actual decorator we'll return def decor(f): for label in labels: setattr(f,label,True) return f # Apply the user's docstring, or autogenerate a basic one if ds is None: ds = "Labels a test as %r." % label decor.__doc__ = ds return decor # Inspired by numpy's skipif, but uses the full apply_wrapper utility to # preserve function metadata better and allows the skip condition to be a # callable. def skipif(skip_condition, msg=None): ''' Make function raise SkipTest exception if skip_condition is true Parameters ---------- skip_condition : bool or callable Flag to determine whether to skip test. If the condition is a callable, it is used at runtime to dynamically make the decision. This is useful for tests that may require costly imports, to delay the cost until the test suite is actually executed. msg : string Message to give on raising a SkipTest exception. Returns ------- decorator : function Decorator, which, when applied to a function, causes SkipTest to be raised when the skip_condition was True, and the function to be called normally otherwise. Notes ----- You will see from the code that we had to further decorate the decorator with the nose.tools.make_decorator function in order to transmit function name, and various other metadata. ''' def skip_decorator(f): # Local import to avoid a hard nose dependency and only incur the # import time overhead at actual test-time. import nose # Allow for both boolean or callable skip conditions. if callable(skip_condition): skip_val = skip_condition else: skip_val = lambda : skip_condition def get_msg(func,msg=None): """Skip message with information about function being skipped.""" if msg is None: out = 'Test skipped due to test condition.' else: out = msg return "Skipping test: %s. %s" % (func.__name__,out) # We need to define *two* skippers because Python doesn't allow both # return with value and yield inside the same function. def skipper_func(*args, **kwargs): """Skipper for normal test functions.""" if skip_val(): raise nose.SkipTest(get_msg(f,msg)) else: return f(*args, **kwargs) def skipper_gen(*args, **kwargs): """Skipper for test generators.""" if skip_val(): raise nose.SkipTest(get_msg(f,msg)) else: for x in f(*args, **kwargs): yield x # Choose the right skipper to use when building the actual generator. if nose.util.isgenerator(f): skipper = skipper_gen else: skipper = skipper_func return nose.tools.make_decorator(f)(skipper) return skip_decorator # A version with the condition set to true, common case just to attach a message # to a skip decorator def skip(msg=None): """Decorator factory - mark a test function for skipping from test suite. Parameters ---------- msg : string Optional message to be added. Returns ------- decorator : function Decorator, which, when applied to a function, causes SkipTest to be raised, with the optional message added. """ return skipif(True,msg) def onlyif(condition, msg): """The reverse from skipif, see skipif for details.""" if callable(condition): skip_condition = lambda : not condition() else: skip_condition = lambda : not condition return skipif(skip_condition, msg) #----------------------------------------------------------------------------- # Utility functions for decorators def module_not_available(module): """Can module be imported? Returns true if module does NOT import. This is used to make a decorator to skip tests that require module to be available, but delay the 'import numpy' to test execution time. """ try: mod = import_module(module) mod_not_avail = False except ImportError: mod_not_avail = True return mod_not_avail def decorated_dummy(dec, name): """Return a dummy function decorated with dec, with the given name. Examples -------- import IPython.testing.decorators as dec setup = dec.decorated_dummy(dec.skip_if_no_x11, __name__) """ warnings.warn("The function `make_label_dec` is deprecated and might be removed in IPython 5.0", DeprecationWarning) dummy = lambda: None dummy.__name__ = name return dec(dummy) #----------------------------------------------------------------------------- # Decorators for public use # Decorators to skip certain tests on specific platforms. skip_win32 = skipif(sys.platform == 'win32', "This test does not run under Windows") skip_linux = skipif(sys.platform.startswith('linux'), "This test does not run under Linux") skip_osx = skipif(sys.platform == 'darwin',"This test does not run under OS X") # Decorators to skip tests if not on specific platforms. skip_if_not_win32 = skipif(sys.platform != 'win32', "This test only runs under Windows") skip_if_not_linux = skipif(not sys.platform.startswith('linux'), "This test only runs under Linux") skip_if_not_osx = skipif(sys.platform != 'darwin', "This test only runs under OSX") _x11_skip_cond = (sys.platform not in ('darwin', 'win32') and os.environ.get('DISPLAY', '') == '') _x11_skip_msg = "Skipped under *nix when X11/XOrg not available" skip_if_no_x11 = skipif(_x11_skip_cond, _x11_skip_msg) # not a decorator itself, returns a dummy function to be used as setup def skip_file_no_x11(name): warnings.warn("The function `skip_file_no_x11` is deprecated and might be removed in IPython 5.0", DeprecationWarning) return decorated_dummy(skip_if_no_x11, name) if _x11_skip_cond else None # Other skip decorators # generic skip without module skip_without = lambda mod: skipif(module_not_available(mod), "This test requires %s" % mod) skipif_not_numpy = skip_without('numpy') skipif_not_matplotlib = skip_without('matplotlib') skipif_not_sympy = skip_without('sympy') skip_known_failure = knownfailureif(True,'This test is known to fail') known_failure_py3 = knownfailureif(sys.version_info[0] >= 3, 'This test is known to fail on Python 3.') py2_only = skipif(PY3, "This test only runs on Python 2.") py3_only = skipif(PY2, "This test only runs on Python 3.") # A null 'decorator', useful to make more readable code that needs to pick # between different decorators based on OS or other conditions null_deco = lambda f: f # Some tests only run where we can use unicode paths. Note that we can't just # check os.path.supports_unicode_filenames, which is always False on Linux. try: f = tempfile.NamedTemporaryFile(prefix=u"tmp€") except UnicodeEncodeError: unicode_paths = False else: unicode_paths = True f.close() onlyif_unicode_paths = onlyif(unicode_paths, ("This test is only applicable " "where we can use unicode in filenames.")) def onlyif_cmds_exist(*commands): """ Decorator to skip test when at least one of `commands` is not found. """ for cmd in commands: if not which(cmd): return skip("This test runs only if command '{0}' " "is installed".format(cmd)) return null_deco def onlyif_any_cmd_exists(*commands): """ Decorator to skip test unless at least one of `commands` is found. """ warnings.warn("The function `onlyif_any_cmd_exists` is deprecated and might be removed in IPython 5.0", DeprecationWarning) for cmd in commands: if which(cmd): return null_deco return skip("This test runs only if one of the commands {0} " "is installed".format(commands))