Source code for nose2.util

# This module contains some code copied from unittest2/loader.py and other
# code developed in reference to that module and others within unittest2.

# unittest2 is Copyright (c) 2001-2010 Python Software Foundation; All
# Rights Reserved. See: http://docs.python.org/license.html

import logging
import os
import types
import re
import sys
import traceback
import platform
import six
import inspect
from inspect import isgeneratorfunction


__unittest = True
IDENT_RE = re.compile(r'^[_a-zA-Z]\w*$', re.UNICODE)
VALID_MODULE_RE = re.compile(r'[_a-zA-Z]\w*\.py$', re.UNICODE)


[docs]def ln(label, char='-', width=70): """Draw a divider, with ``label`` in the middle. >>> ln('hello there') '---------------------------- hello there -----------------------------' ``width`` and divider ``char`` may be specified. Defaults are ``70`` and ``'-'``, respectively. """ label_len = len(label) + 2 chunk = (width - label_len) // 2 out = '%s %s %s' % (char * chunk, label, char * chunk) pad = width - len(out) if pad > 0: out = out + (char * pad) return out
[docs]def valid_module_name(path): """Is ``path`` a valid module name?""" return VALID_MODULE_RE.search(path)
[docs]def name_from_path(path): """Translate ``path`` into module name Returns a two-element tuple: 1. a dotted module name that can be used in an import statement (e.g., ``pkg1.test.test_things``) 2. a full path to filesystem directory, which must be on ``sys.path`` for the import to succeed. """ # back up to find module root parts = [] path = os.path.normpath(path) base = os.path.splitext(path)[0] candidate, top = os.path.split(base) parts.append(top) while candidate: if ispackage(candidate): candidate, top = os.path.split(candidate) parts.append(top) else: break return '.'.join(reversed(parts)), candidate
[docs]def module_from_name(name): """Import module from ``name``""" __import__(name) return sys.modules[name]
[docs]def test_from_name(name, module): """Import test from ``name``""" pos = name.find(':') index = None if pos != -1: real_name, digits = name[:pos], name[pos + 1:] try: index = int(digits) except ValueError: pass else: name = real_name parent, obj = object_from_name(name, module) return parent, obj, name, index
[docs]def object_from_name(name, module=None): """ Given a dotted name, return the corresponding object. Getting the object can fail for two reason: - the object is a module that cannot be imported. - the object is a class or a function that does not exists. Since we cannot distinguish between these two cases, we assume we are in the first one. We expect the stacktrace is explicit enough for the user to understand the error. """ import_error = None parts = name.split('.') if module is None: (module, import_error) = try_import_module_from_name(parts[:]) parts = parts[1:] parent = None obj = module for part in parts: try: parent, obj = obj, getattr(obj, part) except AttributeError as e: if is_package_or_module(obj) and import_error: # Re-raise the import error which got us here, since # it probably better describes the issue. _raise_custom_attribute_error(obj, part, e, import_error) else: raise return parent, obj
def _raise_custom_attribute_error(obj, attr, attr_error_exc, prev_exc): if sys.version_info >= (3, 0): six.raise_from(attr_error_exc, prev_exc[1]) # for python 2, do exception chaining manually raise AttributeError( "'%s' has not attribute '%s'\n\nMaybe caused by\n\n%s" % ( obj, attr, '\n'.join(traceback.format_exception(*prev_exc)))) def is_package_or_module(obj): if hasattr(obj, '__path__') or isinstance(obj, types.ModuleType): return True return False
[docs]def try_import_module_from_name(splitted_name): """ Try to find the longest importable from the ``splitted_name``, and return the corresponding module, as well as the potential ``ImportError`` exception that occurs when trying to import a longer name. For instance, if ``splitted_name`` is ['a', 'b', 'c'] but only ``a.b`` is importable, this function: 1. tries to import ``a.b.c`` and fails 2. tries to import ``a.b`` and succeeds 3. return ``a.b`` and the exception that occured at step 1. """ module = None import_error = None while splitted_name: try: module = __import__('.'.join(splitted_name)) break except: import_error = sys.exc_info() del splitted_name[-1] if not splitted_name: six.reraise(*sys.exc_info()) return (module, import_error)
[docs]def name_from_args(name, index, args): """Create test name from test args""" summary = ', '.join(repr(arg) for arg in args) return '%s:%s\n%s' % (name, index + 1, summary[:79])
def test_name(test, qualname=True): # XXX does not work for test funcs; test.id() lacks module if hasattr(test, '_funcName'): tid = test._funcName elif hasattr(test, '_testFunc'): tid = "%s.%s" % (test._testFunc.__module__, test._testFunc.__name__) else: if sys.version_info >= (3, 5) and not qualname: test_module = test.__class__.__module__ test_class = test.__class__.__name__ test_method = test._testMethodName tid = "%s.%s.%s" % (test_module, test_class, test_method) else: tid = test.id() if '\n' in tid: tid = tid.split('\n')[0] return tid
[docs]def ispackage(path): """Is this path a package directory?""" if os.path.isdir(path): # at least the end of the path must be a legal python identifier # and __init__.py[co] must exist end = os.path.basename(path) if IDENT_RE.match(end): for init in ('__init__.py', '__init__.pyc', '__init__.pyo'): if os.path.isfile(os.path.join(path, init)): return True if sys.platform.startswith('java') and \ os.path.isfile(os.path.join(path, '__init__$py.class')): return True return False
[docs]def ensure_importable(dirname): """Ensure a directory is on ``sys.path``.""" if dirname not in sys.path: sys.path.insert(0, dirname)
[docs]def isgenerator(obj): """Is this object a generator?""" return (isgeneratorfunction(obj) or getattr(obj, 'testGenerator', None) is not None)
[docs]def has_module_fixtures(test): """Does this test live in a module with module fixtures?""" modname = test.__class__.__module__ try: mod = sys.modules[modname] except KeyError: return return hasattr(mod, 'setUpModule') or hasattr(mod, 'tearDownModule')
def has_class_fixtures(test): # hasattr would be the obvious thing to use here. Unfortunately, all tests # inherit from unittest2.case.TestCase, and that *always* has setUpClass and # tearDownClass methods. Thus, exclude the unitest and unittest2 base # classes from the lookup. def is_not_base_class(c): return ( "unittest.case" not in c.__module__ and "unittest2.case" not in c.__module__) has_class_setups = any( 'setUpClass' in c.__dict__ for c in test.__class__.__mro__ if is_not_base_class(c)) has_class_teardowns = any( 'tearDownClass' in c.__dict__ for c in test.__class__.__mro__ if is_not_base_class(c)) return has_class_setups or has_class_teardowns
[docs]def safe_decode(string): """Safely decode a byte string into unicode""" if string is None: return string try: return string.decode() except AttributeError: return string except UnicodeDecodeError: pass try: return string.decode('utf-8') except UnicodeDecodeError: return six.u('<unable to decode>')
def safe_encode(string, encoding='utf-8'): if string is None: return string if encoding is None: encoding = 'utf-8' try: return string.encode(encoding) except AttributeError: return string except UnicodeDecodeError: # already encoded return string except UnicodeEncodeError: return six.u('<unable to encode>')
[docs]def exc_info_to_string(err, test): """Format exception info for output""" formatTraceback = getattr(test, 'formatTraceback', None) if formatTraceback is not None: return test.formatTraceback(err) else: return format_traceback(test, err)
[docs]def format_traceback(test, err): """Converts a :func:`sys.exc_info` -style tuple of values into a string.""" exctype, value, tb = err if not hasattr(tb, 'tb_next'): msgLines = tb else: # Skip test runner traceback levels while tb and _is_relevant_tb_level(tb): tb = tb.tb_next failure = getattr(test, 'failureException', AssertionError) if exctype is failure: # Skip assert*() traceback levels length = _count_relevant_tb_levels(tb) msgLines = traceback.format_exception(exctype, value, tb, length) else: msgLines = traceback.format_exception(exctype, value, tb) return ''.join(msgLines)
[docs]def transplant_class(cls, module): """Make ``cls`` appear to reside in ``module``. :param cls: A class :param module: A module name :returns: A subclass of ``cls`` that appears to have been defined in ``module``. The returned class's ``__name__`` will be equal to ``cls.__name__``, and its ``__module__`` equal to ``module``. """ class C(cls): pass C.__module__ = module C.__name__ = cls.__name__ return C
[docs]def parse_log_level(lvl): """Return numeric log level given a string""" try: return int(lvl) except ValueError: pass return getattr(logging, lvl.upper(), logging.WARN)
def _is_relevant_tb_level(tb): return '__unittest' in tb.tb_frame.f_globals def _count_relevant_tb_levels(tb): length = 0 while tb and not _is_relevant_tb_level(tb): length += 1 tb = tb.tb_next return length class _WritelnDecorator(object): """Used to decorate file-like objects with a handy :func:`writeln` method""" def __init__(self, stream): self.stream = stream def __getattr__(self, attr): if attr in ('stream', '__getstate__'): raise AttributeError(attr) return getattr(self.stream, attr) def write(self, arg): if sys.version_info[0] == 2: arg = safe_encode(arg, getattr(self.stream, 'encoding', 'utf-8')) self.stream.write(arg) def writeln(self, arg=None): if arg: self.write(arg) self.write('\n') # text-mode streams translate to \r\n if needed def ancestry(layer): layers = [[layer]] bases = [base for base in bases_and_mixins(layer) if base is not object] while bases: layers.append(bases) newbases = [] for b in bases: for bb in bases_and_mixins(b): if bb is not object: newbases.append(bb) bases = newbases layers.reverse() return layers def bases_and_mixins(layer): return (layer.__bases__ + getattr(layer, 'mixins', ()))
[docs]def num_expected_args(func): """Return the number of arguments that :func: expects""" if six.PY2: return len(inspect.getargspec(func)[0]) else: return len(inspect.getfullargspec(func)[0])
[docs]def call_with_args_if_expected(func, *args): """Take :func: and call it with supplied :args:, in case that signature expects any. Otherwise call the function without any arguments. """ if num_expected_args(func) > 0: func(*args) else: func()