Merge branch 'master' into pr1145

CHANGES.rst

-v36.5.1
+v36.6.1
 -------
 
-* #170: When working with Mercurial checkouts, use Windows-friendly
-  syntax for suppressing output.
+* #1132: Removed redundant and costly serialization/parsing step
+  in ``EntryPoint.__init__``.
+
+v36.6.0
+-------
+
+* #1143: Added ``setuptools.build_meta`` module, an implementation
+  of PEP-517 for Setuptools-defined packages.
+
+* #1143: Added ``dist_info`` command for producing dist_info
+  metadata.
 
 v36.5.0
 -------
 
+* #170: When working with Mercurial checkouts, use Windows-friendly
+  syntax for suppressing output.
+
 * Inspired by #1134, performed substantial refactoring of
   ``pkg_resources.find_on_path`` to facilitate an optimization
   for paths with many non-version entries.

pkg_resources/__init__.py

@@ -480,8 +480,10 @@ def get_build_platform():
         try:
             version = _macosx_vers()
             machine = os.uname()[4].replace(" ", "_")
-            return "macosx-%d.%d-%s" % (int(version[0]), int(version[1]),
-                _macosx_arch(machine))
+            return "macosx-%d.%d-%s" % (
+                int(version[0]), int(version[1]),
+                _macosx_arch(machine),
+            )
         except ValueError:
             # if someone is running a non-Mac darwin system, this will fall
             # through to the default implementation
@@ -806,7 +808,8 @@ class WorkingSet(object):
         already-installed distribution; it should return a ``Distribution`` or
         ``None``.
 
-        Unless `replace_conflicting=True`, raises a VersionConflict exception if
+        Unless `replace_conflicting=True`, raises a VersionConflict exception
+        if
         any requirements are found on the path that have the correct name but
         the wrong version.  Otherwise, if an `installer` is supplied it will be
         invoked to obtain the correct version of the requirement and activate
@@ -885,8 +888,8 @@ class WorkingSet(object):
         # return list of distros to activate
         return to_activate
 
-    def find_plugins(self, plugin_env, full_env=None, installer=None,
-            fallback=True):
+    def find_plugins(
+            self, plugin_env, full_env=None, installer=None, fallback=True):
         """Find all activatable distributions in `plugin_env`
 
         Example usage::
@@ -1040,7 +1043,8 @@ class _ReqExtras(dict):
 class Environment(object):
     """Searchable snapshot of distributions on a search path"""
 
-    def __init__(self, search_path=None, platform=get_supported_platform(),
+    def __init__(
+            self, search_path=None, platform=get_supported_platform(),
             python=PY_MAJOR):
         """Snapshot distributions available on a search path
 
@@ -1113,7 +1117,8 @@ class Environment(object):
                 dists.append(dist)
                 dists.sort(key=operator.attrgetter('hashcmp'), reverse=True)
 
-    def best_match(self, req, working_set, installer=None, replace_conflicting=False):
+    def best_match(
+            self, req, working_set, installer=None, replace_conflicting=False):
         """Find distribution best matching `req` and usable on `working_set`
 
         This calls the ``find(req)`` method of the `working_set` to see if a
@@ -1248,8 +1253,8 @@ class ResourceManager:
         tmpl = textwrap.dedent("""
             Can't extract file(s) to egg cache
 
-            The following error occurred while trying to extract file(s) to the Python egg
-            cache:
+            The following error occurred while trying to extract file(s)
+            to the Python egg cache:
 
               {old_exc}
 
@@ -1257,9 +1262,9 @@ class ResourceManager:
 
               {cache_path}
 
-            Perhaps your account does not have write access to this directory?  You can
-            change the cache directory by setting the PYTHON_EGG_CACHE environment
-            variable to point to an accessible directory.
+            Perhaps your account does not have write access to this directory?
+            You can change the cache directory by setting the PYTHON_EGG_CACHE
+            environment variable to point to an accessible directory.
             """).lstrip()
         err = ExtractionError(tmpl.format(**locals()))
         err.manager = self
@@ -1309,11 +1314,13 @@ class ResourceManager:
             return
         mode = os.stat(path).st_mode
         if mode & stat.S_IWOTH or mode & stat.S_IWGRP:
-            msg = ("%s is writable by group/others and vulnerable to attack "
+            msg = (
+                "%s is writable by group/others and vulnerable to attack "
                 "when "
                 "used with get_resource_filename. Consider a more secure "
                 "location (set with .set_extraction_path or the "
-                "PYTHON_EGG_CACHE environment variable)." % path)
+                "PYTHON_EGG_CACHE environment variable)." % path
+            )
             warnings.warn(msg, UserWarning)
 
     def postprocess(self, tempname, filename):
@@ -1597,8 +1604,11 @@ class DefaultProvider(EggProvider):
 
     @classmethod
     def _register(cls):
-        loader_cls = getattr(importlib_machinery, 'SourceFileLoader',
-            type(None))
+        loader_cls = getattr(
+            importlib_machinery,
+            'SourceFileLoader',
+            type(None),
+        )
         register_loader_type(loader_cls, cls)
 
 
@@ -1766,7 +1776,10 @@ class ZipProvider(EggProvider):
             if self._is_current(real_path, zip_path):
                 return real_path
 
-            outf, tmpnam = _mkstemp(".$extract", dir=os.path.dirname(real_path))
+            outf, tmpnam = _mkstemp(
+                ".$extract",
+                dir=os.path.dirname(real_path),
+            )
             os.write(outf, self.loader.get_data(zip_path))
             os.close(outf)
             utime(tmpnam, (timestamp, timestamp))
@@ -1972,7 +1985,8 @@ def find_eggs_in_zip(importer, path_item, only=False):
     for subitem in metadata.resource_listdir('/'):
         if _is_egg_path(subitem):
             subpath = os.path.join(path_item, subitem)
-            for dist in find_eggs_in_zip(zipimport.zipimporter(subpath), subpath):
+            dists = find_eggs_in_zip(zipimport.zipimporter(subpath), subpath)
+            for dist in dists:
                 yield dist
         elif subitem.lower().endswith('.dist-info'):
             subpath = os.path.join(path_item, subitem)
@@ -1981,7 +1995,6 @@ def find_eggs_in_zip(importer, path_item, only=False):
             yield Distribution.from_location(path_item, subitem, submeta)
 
 
-
 register_finder(zipimport.zipimporter, find_eggs_in_zip)
 
 
@@ -2124,7 +2137,11 @@ def non_empty_lines(path):
     """
     Yield non-empty lines from file at path
     """
-    return (line.rstrip() for line in open(path) if line.strip())
+    with open(path) as f:
+        for line in f:
+            line = line.strip()
+            if line:
+                yield line
 
 
 def resolve_egg_link(path):
@@ -2375,7 +2392,7 @@ class EntryPoint(object):
         self.name = name
         self.module_name = module_name
         self.attrs = tuple(attrs)
-        self.extras = Requirement.parse(("x[%s]" % ','.join(extras))).extras
+        self.extras = tuple(extras)
         self.dist = dist
 
     def __str__(self):
@@ -2523,7 +2540,8 @@ class Distribution(object):
     """Wrap an actual or potential sys.path entry w/metadata"""
     PKG_INFO = 'PKG-INFO'
 
-    def __init__(self, location=None, metadata=None, project_name=None,
+    def __init__(
+            self, location=None, metadata=None, project_name=None,
             version=None, py_version=PY_MAJOR, platform=None,
             precedence=EGG_DIST):
         self.project_name = safe_name(project_name or 'Unknown')
@@ -2799,7 +2817,8 @@ class Distribution(object):
                 if replace:
                     break
                 else:
-                    # don't modify path (even removing duplicates) if found and not replace
+                    # don't modify path (even removing duplicates) if
+                    # found and not replace
                     return
             elif item == bdir and self.precedence == EGG_DIST:
                 # if it's an .egg, give it precedence over its directory
@@ -2896,7 +2915,10 @@ class EggInfoDistribution(Distribution):
 
 
 class DistInfoDistribution(Distribution):
-    """Wrap an actual or potential sys.path entry w/metadata, .dist-info style"""
+    """
+    Wrap an actual or potential sys.path entry
+    w/metadata, .dist-info style.
+    """
     PKG_INFO = 'METADATA'
     EQEQ = re.compile(r"([\(,])\s*(\d.*?)\s*([,\)])")
 
@@ -2946,7 +2968,7 @@ _distributionImpl = {
     '.egg': Distribution,
     '.egg-info': EggInfoDistribution,
     '.dist-info': DistInfoDistribution,
-    }
+}
 
 
 def issue_warning(*args, **kw):
@@ -3031,7 +3053,8 @@ class Requirement(packaging.requirements.Requirement):
     def __hash__(self):
         return self.__hash
 
-    def __repr__(self): return "Requirement.parse(%r)" % str(self)
+    def __repr__(self):
+        return "Requirement.parse(%r)" % str(self)
 
     @staticmethod
     def parse(s):
@@ -3165,7 +3188,10 @@ def _initialize_master_working_set():
         dist.activate(replace=False)
         for dist in working_set
     )
-    add_activation_listener(lambda dist: dist.activate(replace=True), existing=False)
+    add_activation_listener(
+        lambda dist: dist.activate(replace=True),
+        existing=False,
+    )
     working_set.entries = []
     # match order
     list(map(working_set.add_entry, sys.path))

pkg_resources/tests/test_pkg_resources.py

@@ -92,8 +92,8 @@ class TestZipProvider(object):
         ts = timestamp(self.ref_time)
         os.utime(filename, (ts, ts))
         filename = zp.get_resource_filename(manager, 'data.dat')
-        f = open(filename)
-        assert f.read() == 'hello, world!'
+        with open(filename) as f:
+            assert f.read() == 'hello, world!'
         manager.cleanup_resources()
 
 

setup.cfg

 [bumpversion]
-current_version = 36.4.0
+current_version = 36.6.0
 commit = True
 tag = True
 
@@ -22,5 +22,7 @@ formats = zip
 [bdist_wheel]
 universal = 1
 
-[bumpversion:file:setup.py]
+[metadata]
+license_file = LICENSE
 
+[bumpversion:file:setup.py]

setup.py

@@ -89,7 +89,7 @@ def pypi_link(pkg_filename):
 
 setup_params = dict(
     name="setuptools",
-    version="36.4.0",
+    version="36.6.0",
     description="Easily download, build, install, upgrade, and uninstall "
         "Python packages",
     author="Python Packaging Authority",

setuptools/build_meta.py

+"""A PEP 517 interface to setuptools
+
+Previously, when a user or a command line tool (let's call it a "frontend")
+needed to make a request of setuptools to take a certain action, for
+example, generating a list of installation requirements, the frontend would
+would call "setup.py egg_info" or "setup.py bdist_wheel" on the command line.
+
+PEP 517 defines a different method of interfacing with setuptools. Rather
+than calling "setup.py" directly, the frontend should:
+
+  1. Set the current directory to the directory with a setup.py file
+  2. Import this module into a safe python interpreter (one in which
+     setuptools can potentially set global variables or crash hard).
+  3. Call one of the functions defined in PEP 517.
+
+What each function does is defined in PEP 517. However, here is a "casual"
+definition of the functions (this definition should not be relied on for
+bug reports or API stability):
+
+  - `build_wheel`: build a wheel in the folder and return the basename
+  - `get_requires_for_build_wheel`: get the `setup_requires` to build
+  - `prepare_metadata_for_build_wheel`: get the `install_requires`
+  - `build_sdist`: build an sdist in the folder and return the basename
+  - `get_requires_for_build_sdist`: get the `setup_requires` to build
+
+Again, this is not a formal definition! Just a "taste" of the module.
+"""
+
+import os
+import sys
+import tokenize
+import shutil
+import contextlib
+
+import setuptools
+import distutils
+
+
+class SetupRequirementsError(BaseException):
+    def __init__(self, specifiers):
+        self.specifiers = specifiers
+
+
+class Distribution(setuptools.dist.Distribution):
+    def fetch_build_eggs(self, specifiers):
+        raise SetupRequirementsError(specifiers)
+
+    @classmethod
+    @contextlib.contextmanager
+    def patch(cls):
+        """
+        Replace
+        distutils.dist.Distribution with this class
+        for the duration of this context.
+        """
+        orig = distutils.core.Distribution
+        distutils.core.Distribution = cls
+        try:
+            yield
+        finally:
+            distutils.core.Distribution = orig
+
+
+def _run_setup(setup_script='setup.py'):
+    # Note that we can reuse our build directory between calls
+    # Correctness comes first, then optimization later
+    __file__ = setup_script
+    f = getattr(tokenize, 'open', open)(__file__)
+    code = f.read().replace('\\r\\n', '\\n')
+    f.close()
+    exec(compile(code, __file__, 'exec'))
+
+
+def _fix_config(config_settings):
+    config_settings = config_settings or {}
+    config_settings.setdefault('--global-option', [])
+    return config_settings
+
+
+def _get_build_requires(config_settings):
+    config_settings = _fix_config(config_settings)
+    requirements = ['setuptools', 'wheel']
+
+    sys.argv = sys.argv[:1] + ['egg_info'] + \
+        config_settings["--global-option"]
+    try:
+        with Distribution.patch():
+            _run_setup()
+    except SetupRequirementsError as e:
+        requirements += e.specifiers
+
+    return requirements
+
+
+def get_requires_for_build_wheel(config_settings=None):
+    config_settings = _fix_config(config_settings)
+    return _get_build_requires(config_settings)
+
+
+def get_requires_for_build_sdist(config_settings=None):
+    config_settings = _fix_config(config_settings)
+    return _get_build_requires(config_settings)
+
+
+def prepare_metadata_for_build_wheel(metadata_directory, config_settings=None):
+    sys.argv = sys.argv[:1] + ['dist_info', '--egg-base', metadata_directory]
+    _run_setup()
+
+    dist_infos = [f for f in os.listdir(metadata_directory)
+                  if f.endswith('.dist-info')]
+
+    assert len(dist_infos) == 1
+    return dist_infos[0]
+
+
+def build_wheel(wheel_directory, config_settings=None,
+                metadata_directory=None):
+    config_settings = _fix_config(config_settings)
+    wheel_directory = os.path.abspath(wheel_directory)
+    sys.argv = sys.argv[:1] + ['bdist_wheel'] + \
+        config_settings["--global-option"]
+    _run_setup()
+    if wheel_directory != 'dist':
+        shutil.rmtree(wheel_directory)
+        shutil.copytree('dist', wheel_directory)
+
+    wheels = [f for f in os.listdir(wheel_directory)
+              if f.endswith('.whl')]
+
+    assert len(wheels) == 1
+    return wheels[0]
+
+
+def build_sdist(sdist_directory, config_settings=None):
+    config_settings = _fix_config(config_settings)
+    sdist_directory = os.path.abspath(sdist_directory)
+    sys.argv = sys.argv[:1] + ['sdist'] + \
+        config_settings["--global-option"]
+    _run_setup()
+    if sdist_directory != 'dist':
+        shutil.rmtree(sdist_directory)
+        shutil.copytree('dist', sdist_directory)
+
+    sdists = [f for f in os.listdir(sdist_directory)
+              if f.endswith('.tar.gz')]
+
+    assert len(sdists) == 1
+    return sdists[0]

setuptools/command/__init__.py

@@ -3,6 +3,7 @@ __all__ = [
     'easy_install', 'egg_info', 'install', 'install_lib', 'rotate', 'saveopts',
     'sdist', 'setopt', 'test', 'install_egg_info', 'install_scripts',
     'register', 'bdist_wininst', 'upload_docs', 'upload', 'build_clib',
+    'dist_info',
 ]
 
 from distutils.command.bdist import bdist

setuptools/command/develop.py

@@ -95,7 +95,9 @@ class develop(namespaces.DevelopInstaller, easy_install):
         path_to_setup = egg_base.replace(os.sep, '/').rstrip('/')
         if path_to_setup != os.curdir:
             path_to_setup = '../' * (path_to_setup.count('/') + 1)
-        resolved = normalize_path(os.path.join(install_dir, egg_path, path_to_setup))
+        resolved = normalize_path(
+            os.path.join(install_dir, egg_path, path_to_setup)
+        )
         if resolved != normalize_path(os.curdir):
             raise DistutilsOptionError(
                 "Can't get a consistent path to setup script from"

setuptools/command/dist_info.py

+"""
+Create a dist_info directory
+As defined in the wheel specification
+"""
+
+import os
+import shutil
+
+from distutils.core import Command
+from distutils import log
+
+
+class dist_info(Command):
+
+    description = 'create a .dist-info directory'
+
+    user_options = [
+        ('egg-base=', 'e', "directory containing .egg-info directories"
+                           " (default: top of the source tree)"),
+    ]
+
+    def initialize_options(self):
+        self.egg_base = None
+
+    def finalize_options(self):
+        pass
+
+    def run(self):
+        egg_info = self.get_finalized_command('egg_info')
+        egg_info.run()
+        dist_info_dir = egg_info.egg_info[:-len('.egg-info')] + '.dist-info'
+        log.info("creating '{}'".format(os.path.abspath(dist_info_dir)))
+
+        bdist_wheel = self.get_finalized_command('bdist_wheel')
+        bdist_wheel.egg2dist(egg_info.egg_info, dist_info_dir)
+
+        if self.egg_base:
+            destination = os.path.join(self.egg_base, dist_info_dir)
+            log.info("creating '{}'".format(os.path.abspath(destination)))
+            shutil.move(dist_info_dir, destination)

setuptools/command/easy_install.py

@@ -1817,7 +1817,7 @@ def _update_zipimporter_cache(normalized_path, cache, updater=None):
         #    get/del patterns instead. For more detailed information see the
         #    following links:
         #      https://github.com/pypa/setuptools/issues/202#issuecomment-202913420
-        #      https://bitbucket.org/pypy/pypy/src/dd07756a34a41f674c0cacfbc8ae1d4cc9ea2ae4/pypy/module/zipimport/interp_zipimport.py#cl-99
+        #      http://bit.ly/2h9itJX
         old_entry = cache[p]
         del cache[p]
         new_entry = updater and updater(p, old_entry)

setuptools/tests/test_build_meta.py

+import os
+
+import pytest
+
+from .files import build_files
+from .textwrap import DALS
+
+
+futures = pytest.importorskip('concurrent.futures')
+importlib = pytest.importorskip('importlib')
+
+
+class BuildBackendBase(object):
+    def __init__(self, cwd=None, env={}, backend_name='setuptools.build_meta'):
+        self.cwd = cwd
+        self.env = env
+        self.backend_name = backend_name
+
+
+class BuildBackend(BuildBackendBase):
+    """PEP 517 Build Backend"""
+    def __init__(self, *args, **kwargs):
+        super(BuildBackend, self).__init__(*args, **kwargs)
+        self.pool = futures.ProcessPoolExecutor()
+
+    def __getattr__(self, name):
+        """Handles aribrary function invocations on the build backend."""
+        def method(*args, **kw):
+            root = os.path.abspath(self.cwd)
+            caller = BuildBackendCaller(root, self.env, self.backend_name)
+            return self.pool.submit(caller, name, *args, **kw).result()
+
+        return method
+
+
+class BuildBackendCaller(BuildBackendBase):
+    def __call__(self, name, *args, **kw):
+        """Handles aribrary function invocations on the build backend."""
+        os.chdir(self.cwd)
+        os.environ.update(self.env)
+        mod = importlib.import_module(self.backend_name)
+        return getattr(mod, name)(*args, **kw)
+
+
+@pytest.fixture
+def build_backend(tmpdir):
+    defn = {
+        'setup.py': DALS("""
+            __import__('setuptools').setup(
+                name='foo',
+                py_modules=['hello'],
+                setup_requires=['six'],
+            )
+            """),
+        'hello.py': DALS("""
+            def run():
+                print('hello')
+            """),
+    }
+    build_files(defn, prefix=str(tmpdir))
+    with tmpdir.as_cwd():
+        yield BuildBackend(cwd='.')
+
+
+def test_get_requires_for_build_wheel(build_backend):
+    actual = build_backend.get_requires_for_build_wheel()
+    expected = ['six', 'setuptools', 'wheel']
+    assert sorted(actual) == sorted(expected)
+
+
+def test_build_wheel(build_backend):
+    dist_dir = os.path.abspath('pip-wheel')
+    os.makedirs(dist_dir)
+    wheel_name = build_backend.build_wheel(dist_dir)
+
+    assert os.path.isfile(os.path.join(dist_dir, wheel_name))
+
+
+def test_build_sdist(build_backend):
+    dist_dir = os.path.abspath('pip-sdist')
+    os.makedirs(dist_dir)
+    sdist_name = build_backend.build_sdist(dist_dir)
+
+    assert os.path.isfile(os.path.join(dist_dir, sdist_name))
+
+
+def test_prepare_metadata_for_build_wheel(build_backend):
+    dist_dir = os.path.abspath('pip-dist-info')
+    os.makedirs(dist_dir)
+
+    dist_info = build_backend.prepare_metadata_for_build_wheel(dist_dir)
+
+    assert os.path.isfile(os.path.join(dist_dir, dist_info, 'METADATA'))

setuptools/tests/test_develop.py

@@ -167,7 +167,9 @@ class TestNamespaces:
         target = tmpdir / 'packages'
         # use pip to install to the target directory
         install_cmd = [
-            'pip',
+            sys.executable,
+            '-m',
+            'pip.__main__',
             'install',
             str(pkg_A),
             '-t', str(target),

setuptools/tests/test_egg_info.py

@@ -164,7 +164,8 @@ class TestEggInfo(object):
         self._run_install_command(tmpdir_cwd, env)
         egg_info_dir = self._find_egg_info_files(env.paths['lib']).base
         sources_txt = os.path.join(egg_info_dir, 'SOURCES.txt')
-        assert 'docs/usage.rst' in open(sources_txt).read().split('\n')
+        with open(sources_txt) as f:
+            assert 'docs/usage.rst' in f.read().split('\n')
 
     def _setup_script_with_requires(self, requires, use_setup_cfg=False):
         setup_script = DALS(
@@ -447,7 +448,8 @@ class TestEggInfo(object):
         self._run_install_command(tmpdir_cwd, env)
         egg_info_dir = self._find_egg_info_files(env.paths['lib']).base
         pkginfo = os.path.join(egg_info_dir, 'PKG-INFO')
-        assert 'Requires-Python: >=1.2.3' in open(pkginfo).read().split('\n')
+        with open(pkginfo) as f:
+            assert 'Requires-Python: >=1.2.3' in f.read().split('\n')
 
     def test_manifest_maker_warning_suppression(self):
         fixtures = [

setuptools/tests/test_namespaces.py

@@ -30,7 +30,9 @@ class TestNamespaces:
         targets = site_packages, path_packages
         # use pip to install to the target directory
         install_cmd = [
-            'pip',
+            sys.executable,
+            '-m',
+            'pip.__main__',
             'install',
             str(pkg_A),
             '-t', str(site_packages),
@@ -38,7 +40,9 @@ class TestNamespaces:
         subprocess.check_call(install_cmd)
         namespaces.make_site_dir(site_packages)
         install_cmd = [
-            'pip',
+            sys.executable,
+            '-m',
+            'pip.__main__',
             'install',
             str(pkg_B),
             '-t', str(path_packages),
@@ -88,7 +92,9 @@ class TestNamespaces:
         target = tmpdir / 'packages'
         # use pip to install to the target directory
         install_cmd = [
-            'pip',
+            sys.executable,
+            '-m',
+            'pip.__main__',
             'install',
             str(pkg_A),
             '-t', str(target),

setuptools/tests/test_sdist.py

@@ -19,6 +19,7 @@ from setuptools.command.sdist import sdist
 from setuptools.command.egg_info import manifest_maker
 from setuptools.dist import Distribution
 from setuptools.tests import fail_on_ascii
+from .text import Filenames
 
 py3_only = pytest.mark.xfail(six.PY2, reason="Test runs on Python 3 only")
 
@@ -36,13 +37,7 @@ from setuptools import setup
 setup(**%r)
 """ % SETUP_ATTRS
 
-if six.PY3:
-    LATIN1_FILENAME = 'smörbröd.py'.encode('latin-1')
-else:
-    LATIN1_FILENAME = 'sm\xf6rbr\xf6d.py'
 
-
-# Cannot use context manager because of Python 2.4
 @contextlib.contextmanager
 def quiet():
     old_stdout, old_stderr = sys.stdout, sys.stderr
@@ -53,17 +48,10 @@ def quiet():
         sys.stdout, sys.stderr = old_stdout, old_stderr
 
 
-# Fake byte literals for Python <= 2.5
-def b(s, encoding='utf-8'):
-    if six.PY3:
-        return s.encode(encoding)
-    return s
-
-
 # Convert to POSIX path
 def posix(path):
     if six.PY3 and not isinstance(path, str):
-        return path.replace(os.sep.encode('ascii'), b('/'))
+        return path.replace(os.sep.encode('ascii'), b'/')
     else:
         return path.replace(os.sep, '/')
 
@@ -86,6 +74,21 @@ def read_all_bytes(filename):
         return fp.read()
 
 
+def latin1_fail():
+    try:
+        desc, filename = tempfile.mkstemp(suffix=Filenames.latin_1)
+        os.close(desc)
+        os.remove(filename)
+    except Exception:
+        return True
+
+
+fail_on_latin1_encoded_filenames = pytest.mark.xfail(
+    latin1_fail(),
+    reason="System does not support latin-1 filenames",
+)
+
+
 class TestSdistTest:
     def setup_method(self, method):
         self.temp_dir = tempfile.mkdtemp()
@@ -134,8 +137,8 @@ class TestSdistTest:
 
     def test_defaults_case_sensitivity(self):
         """
-            Make sure default files (README.*, etc.) are added in a case-sensitive
-            way to avoid problems with packages built on Windows.
+        Make sure default files (README.*, etc.) are added in a case-sensitive
+        way to avoid problems with packages built on Windows.
         """
 
         open(os.path.join(self.temp_dir, 'readme.rst'), 'w').close()
@@ -152,7 +155,9 @@ class TestSdistTest:
         with quiet():
             cmd.run()
 
-        # lowercase all names so we can test in a case-insensitive way to make sure the files are not included
+        # lowercase all names so we can test in a
+        # case-insensitive way to make sure the files
+        # are not included.
         manifest = map(lambda x: x.lower(), cmd.filelist.files)
         assert 'readme.rst' not in manifest, manifest
         assert 'setup.py' not in manifest, manifest
@@ -201,8 +206,7 @@ class TestSdistTest:
         mm.manifest = os.path.join('sdist_test.egg-info', 'SOURCES.txt')
         os.mkdir('sdist_test.egg-info')
 
-        # UTF-8 filename
-        filename = os.path.join(b('sdist_test'), b('smörbröd.py'))
+        filename = os.path.join(b'sdist_test', Filenames.utf_8)
 
         # Must touch the file or risk removal
         open(filename, "w").close()
@@ -241,7 +245,7 @@ class TestSdistTest:
         os.mkdir('sdist_test.egg-info')
 
         # Latin-1 filename
-        filename = os.path.join(b('sdist_test'), LATIN1_FILENAME)
+        filename = os.path.join(b'sdist_test', Filenames.latin_1)
 
         # Add filename with surrogates and write manifest
         with quiet():
@@ -275,10 +279,10 @@ class TestSdistTest:
             cmd.run()
 
         # Add UTF-8 filename to manifest
-        filename = os.path.join(b('sdist_test'), b('smörbröd.py'))
+        filename = os.path.join(b'sdist_test', Filenames.utf_8)
         cmd.manifest = os.path.join('sdist_test.egg-info', 'SOURCES.txt')
         manifest = open(cmd.manifest, 'ab')
-        manifest.write(b('\n') + filename)
+        manifest.write(b'\n' + filename)
         manifest.close()
 
         # The file must exist to be included in the filelist
@@ -295,6 +299,7 @@ class TestSdistTest:
         assert filename in cmd.filelist.files
 
     @py3_only
+    @fail_on_latin1_encoded_filenames
     def test_read_manifest_skips_non_utf8_filenames(self):
         # Test for #303.
         dist = Distribution(SETUP_ATTRS)
@@ -307,10 +312,10 @@ class TestSdistTest:
             cmd.run()
 
         # Add Latin-1 filename to manifest
-        filename = os.path.join(b('sdist_test'), LATIN1_FILENAME)
+        filename = os.path.join(b'sdist_test', Filenames.latin_1)
         cmd.manifest = os.path.join('sdist_test.egg-info', 'SOURCES.txt')
         manifest = open(cmd.manifest, 'ab')
-        manifest.write(b('\n') + filename)
+        manifest.write(b'\n' + filename)
         manifest.close()
 
         # The file must exist to be included in the filelist
@@ -326,6 +331,7 @@ class TestSdistTest:
         assert filename not in cmd.filelist.files
 
     @fail_on_ascii
+    @fail_on_latin1_encoded_filenames
     def test_sdist_with_utf8_encoded_filename(self):
         # Test for #303.
         dist = Distribution(SETUP_ATTRS)
@@ -333,8 +339,7 @@ class TestSdistTest:
         cmd = sdist(dist)
         cmd.ensure_finalized()
 
-        # UTF-8 filename
-        filename = os.path.join(b('sdist_test'), b('smörbröd.py'))
+        filename = os.path.join(b'sdist_test', Filenames.utf_8)
         open(filename, 'w').close()
 
         with quiet():
@@ -360,6 +365,7 @@ class TestSdistTest:
         else:
             assert filename in cmd.filelist.files
 
+    @fail_on_latin1_encoded_filenames
     def test_sdist_with_latin1_encoded_filename(self):
         # Test for #303.
         dist = Distribution(SETUP_ATTRS)
@@ -368,7 +374,7 @@ class TestSdistTest:
         cmd.ensure_finalized()
 
         # Latin-1 filename
-        filename = os.path.join(b('sdist_test'), LATIN1_FILENAME)
+        filename = os.path.join(b'sdist_test', Filenames.latin_1)
         open(filename, 'w').close()
         assert os.path.isfile(filename)
 
@@ -381,10 +387,9 @@ class TestSdistTest:
                 # Latin-1 is similar to Windows-1252 however
                 # on mbcs filesys it is not in latin-1 encoding
                 fs_enc = sys.getfilesystemencoding()
-                if fs_enc == 'mbcs':
-                    filename = filename.decode('mbcs')
-                else:
-                    filename = filename.decode('latin-1')
+                if fs_enc != 'mbcs':
+                    fs_enc = 'latin-1'
+                filename = filename.decode(fs_enc)
 
                 assert filename in cmd.filelist.files
             else:

setuptools/tests/text.py

+# -*- coding: utf-8 -*-
+
+from __future__ import unicode_literals
+
+
+class Filenames:
+    unicode = 'smörbröd.py'
+    latin_1 = unicode.encode('latin-1')
+    utf_8 = unicode.encode('utf-8')