← Back
Editing: plugintest.py
""" Testing Plugins =============== The plugin interface is well-tested enough to safely unit test your use of its hooks with some level of confidence. However, there is also a mixin for unittest.TestCase called PluginTester that's designed to test plugins in their native runtime environment. Here's a simple example with a do-nothing plugin and a composed suite. >>> import unittest >>> from nose.plugins import Plugin, PluginTester >>> class FooPlugin(Plugin): ... pass >>> class TestPluginFoo(PluginTester, unittest.TestCase): ... activate = '--with-foo' ... plugins = [FooPlugin()] ... def test_foo(self): ... for line in self.output: ... # i.e. check for patterns ... pass ... ... # or check for a line containing ... ... assert "ValueError" in self.output ... def makeSuite(self): ... class TC(unittest.TestCase): ... def runTest(self): ... raise ValueError("I hate foo") ... return [TC('runTest')] ... >>> res = unittest.TestResult() >>> case = TestPluginFoo('test_foo') >>> _ = case(res) >>> res.errors [] >>> res.failures [] >>> res.wasSuccessful() True >>> res.testsRun 1 And here is a more complex example of testing a plugin that has extra arguments and reads environment variables. >>> import unittest, os >>> from nose.plugins import Plugin, PluginTester >>> class FancyOutputter(Plugin): ... name = "fancy" ... def configure(self, options, conf): ... Plugin.configure(self, options, conf) ... if not self.enabled: ... return ... self.fanciness = 1 ... if options.more_fancy: ... self.fanciness = 2 ... if 'EVEN_FANCIER' in self.env: ... self.fanciness = 3 ... ... def options(self, parser, env=os.environ): ... self.env = env ... parser.add_option('--more-fancy', action='store_true') ... Plugin.options(self, parser, env=env) ... ... def report(self, stream): ... stream.write("FANCY " * self.fanciness) ... >>> class TestFancyOutputter(PluginTester, unittest.TestCase): ... activate = '--with-fancy' # enables the plugin ... plugins = [FancyOutputter()] ... args = ['--more-fancy'] ... env = {'EVEN_FANCIER': '1'} ... ... def test_fancy_output(self): ... assert "FANCY FANCY FANCY" in self.output, ( ... "got: %s" % self.output) ... def makeSuite(self): ... class TC(unittest.TestCase): ... def runTest(self): ... raise ValueError("I hate fancy stuff") ... return [TC('runTest')] ... >>> res = unittest.TestResult() >>> case = TestFancyOutputter('test_fancy_output') >>> _ = case(res) >>> res.errors [] >>> res.failures [] >>> res.wasSuccessful() True >>> res.testsRun 1 """ import re import sys from warnings import warn try: from io import StringIO except ImportError: from io import StringIO __all__ = ['PluginTester', 'run'] from os import getpid class MultiProcessFile(object): """ helper for testing multiprocessing multiprocessing poses a problem for doctests, since the strategy of replacing sys.stdout/stderr with file-like objects then inspecting the results won't work: the child processes will write to the objects, but the data will not be reflected in the parent doctest-ing process. The solution is to create file-like objects which will interact with multiprocessing in a more desirable way. All processes can write to this object, but only the creator can read. This allows the testing system to see a unified picture of I/O. """ def __init__(self): # per advice at: # http://docs.python.org/library/multiprocessing.html#all-platforms self.__master = getpid() self.__queue = Manager().Queue() self.__buffer = StringIO() self.softspace = 0 def buffer(self): if getpid() != self.__master: return from queue import Empty from collections import defaultdict cache = defaultdict(str) while True: try: pid, data = self.__queue.get_nowait() except Empty: break if pid == (): #show parent output after children #this is what users see, usually pid = ( 1e100, ) # googol! cache[pid] += data for pid in sorted(cache): #self.__buffer.write( '%s wrote: %r\n' % (pid, cache[pid]) ) #DEBUG self.__buffer.write( cache[pid] ) def write(self, data): # note that these pids are in the form of current_process()._identity # rather than OS pids from multiprocessing import current_process pid = current_process()._identity self.__queue.put((pid, data)) def __iter__(self): "getattr doesn't work for iter()" self.buffer() return self.__buffer def seek(self, offset, whence=0): self.buffer() return self.__buffer.seek(offset, whence) def getvalue(self): self.buffer() return self.__buffer.getvalue() def __getattr__(self, attr): return getattr(self.__buffer, attr) try: from multiprocessing import Manager Buffer = MultiProcessFile except ImportError: Buffer = StringIO class PluginTester(object): """A mixin for testing nose plugins in their runtime environment. Subclass this and mix in unittest.TestCase to run integration/functional tests on your plugin. When setUp() is called, the stub test suite is executed with your plugin so that during an actual test you can inspect the artifacts of how your plugin interacted with the stub test suite. - activate - the argument to send nosetests to activate the plugin - suitepath - if set, this is the path of the suite to test. Otherwise, you will need to use the hook, makeSuite() - plugins - the list of plugins to make available during the run. Note that this does not mean these plugins will be *enabled* during the run -- only the plugins enabled by the activate argument or other settings in argv or env will be enabled. - args - a list of arguments to add to the nosetests command, in addition to the activate argument - env - optional dict of environment variables to send nosetests """ activate = None suitepath = None args = None env = {} argv = None plugins = [] ignoreFiles = None def makeSuite(self): """returns a suite object of tests to run (unittest.TestSuite()) If self.suitepath is None, this must be implemented. The returned suite object will be executed with all plugins activated. It may return None. Here is an example of a basic suite object you can return :: >>> import unittest >>> class SomeTest(unittest.TestCase): ... def runTest(self): ... raise ValueError("Now do something, plugin!") ... >>> unittest.TestSuite([SomeTest()]) # doctest: +ELLIPSIS <unittest...TestSuite tests=[<...SomeTest testMethod=runTest>]> """ raise NotImplementedError def _execPlugin(self): """execute the plugin on the internal test suite. """ from nose.config import Config from nose.core import TestProgram from nose.plugins.manager import PluginManager suite = None stream = Buffer() conf = Config(env=self.env, stream=stream, plugins=PluginManager(plugins=self.plugins)) if self.ignoreFiles is not None: conf.ignoreFiles = self.ignoreFiles if not self.suitepath: suite = self.makeSuite() self.nose = TestProgram(argv=self.argv, config=conf, suite=suite, exit=False) self.output = AccessDecorator(stream) def setUp(self): """runs nosetests with the specified test suite, all plugins activated. """ self.argv = ['nosetests', self.activate] if self.args: self.argv.extend(self.args) if self.suitepath: self.argv.append(self.suitepath) self._execPlugin() class AccessDecorator(object): stream = None _buf = None def __init__(self, stream): self.stream = stream stream.seek(0) self._buf = stream.read() stream.seek(0) def __contains__(self, val): return val in self._buf def __iter__(self): return iter(self.stream) def __str__(self): return self._buf def blankline_separated_blocks(text): "a bunch of === characters is also considered a blank line" block = [] for line in text.splitlines(True): block.append(line) line = line.strip() if not line or line.startswith('===') and not line.strip('='): yield "".join(block) block = [] if block: yield "".join(block) def remove_stack_traces(out): # this regexp taken from Python 2.5's doctest traceback_re = re.compile(r""" # Grab the traceback header. Different versions of Python have # said different things on the first traceback line. ^(?P<hdr> Traceback\ \( (?: most\ recent\ call\ last | innermost\ last ) \) : ) \s* $ # toss trailing whitespace on the header. (?P<stack> .*?) # don't blink: absorb stuff until... ^(?=\w) # a line *starts* with alphanum. .*?(?P<exception> \w+ ) # exception name (?P<msg> [:\n] .*) # the rest """, re.VERBOSE | re.MULTILINE | re.DOTALL) blocks = [] for block in blankline_separated_blocks(out): blocks.append(traceback_re.sub(r"\g<hdr>\n...\n\g<exception>\g<msg>", block)) return "".join(blocks) def simplify_warnings(out): warn_re = re.compile(r""" # Cut the file and line no, up to the warning name ^.*:\d+:\s (?P<category>\w+): \s+ # warning category (?P<detail>.+) $ \n? # warning message ^ .* $ # stack frame """, re.VERBOSE | re.MULTILINE) return warn_re.sub(r"\g<category>: \g<detail>", out) def remove_timings(out): return re.sub( r"Ran (\d+ tests?) in [0-9.]+s", r"Ran \1 in ...s", out) def munge_nose_output_for_doctest(out): """Modify nose output to make it easy to use in doctests.""" out = remove_stack_traces(out) out = simplify_warnings(out) out = remove_timings(out) return out.strip() def run(*arg, **kw): """ Specialized version of nose.run for use inside of doctests that test test runs. This version of run() prints the result output to stdout. Before printing, the output is processed by replacing the timing information with an ellipsis (...), removing traceback stacks, and removing trailing whitespace. Use this version of run wherever you are writing a doctest that tests nose (or unittest) test result output. Note: do not use doctest: +ELLIPSIS when testing nose output, since ellipses ("test_foo ... ok") in your expected test runner output may match multiple lines of output, causing spurious test passes! """ from nose import run from nose.config import Config from nose.plugins.manager import PluginManager buffer = Buffer() if 'config' not in kw: plugins = kw.pop('plugins', []) if isinstance(plugins, list): plugins = PluginManager(plugins=plugins) env = kw.pop('env', {}) kw['config'] = Config(env=env, plugins=plugins) if 'argv' not in kw: kw['argv'] = ['nosetests', '-v'] kw['config'].stream = buffer # Set up buffering so that all output goes to our buffer, # or warn user if deprecated behavior is active. If this is not # done, prints and warnings will either be out of place or # disappear. stderr = sys.stderr stdout = sys.stdout if kw.pop('buffer_all', False): sys.stdout = sys.stderr = buffer restore = True else: restore = False warn("The behavior of nose.plugins.plugintest.run() will change in " "the next release of nose. The current behavior does not " "correctly account for output to stdout and stderr. To enable " "correct behavior, use run_buffered() instead, or pass " "the keyword argument buffer_all=True to run().", DeprecationWarning, stacklevel=2) try: run(*arg, **kw) finally: if restore: sys.stderr = stderr sys.stdout = stdout out = buffer.getvalue() print(munge_nose_output_for_doctest(out)) def run_buffered(*arg, **kw): kw['buffer_all'] = True run(*arg, **kw) if __name__ == '__main__': import doctest doctest.testmod()
Save File
Cancel