Repository: sympy/sphinx-math-dollar (language: python)

Issue:
Update versioneer
The version of versioneer.py included in the 1.2 release uses SafeConfigParser, which was deprecated in python 3.2 and has been removed entirely from the upcoming python 3.11.  This has been fixed in recent versions of versioneer.  Please update to a more recent version of versioneer.py.  (This was discovered while doing test builds of all Fedora packages with the current alpha version of python 3.11, by the way.)



Discussion / hints:

Fix patch:
diff --git a/.github/workflows/pythonpackage.yml b/.github/workflows/pythonpackage.yml
index fba229b..fdcc513 100644
--- a/.github/workflows/pythonpackage.yml
+++ b/.github/workflows/pythonpackage.yml
@@ -8,12 +8,13 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: [2.7, 3.6, 3.7]
+        python-version: ['3.6', '3.7', '3.8', '3.9', '3.10', 'pypy-3.7',
+                         'pypy-3.8', '3.11.0-alpha.2']
 
     steps:
-    - uses: actions/checkout@v1
+    - uses: actions/checkout@v2
     - name: Set up Python ${{ matrix.python-version }}
-      uses: actions/setup-python@v1
+      uses: actions/setup-python@v2
       with:
         python-version: ${{ matrix.python-version }}
     - name: Install dependencies
@@ -26,5 +27,5 @@ jobs:
         pyflakes .
     - name: Test with pytest
       run: |
-        pip install pytest pytest-doctestplus sphinx-testing
+        pip install pytest pytest-doctestplus
         pytest
diff --git a/docs/__init__.py b/docs/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/setup.py b/setup.py
index 62b2da5..28617f8 100644
--- a/setup.py
+++ b/setup.py
@@ -16,12 +16,11 @@
     url="https://github.com/sympy/sphinx-math-dollar/",
     packages=setuptools.find_packages(),
     classifiers=[
-        "Programming Language :: Python :: 2",
         "Programming Language :: Python :: 3",
         "License :: OSI Approved :: MIT License",
         "Operating System :: OS Independent",
     ],
-    # python_requires= '>=3.6',
+    python_requires= '>=3.6',
     install_requires=[
         'sphinx'
     ],
diff --git a/sphinx_math_dollar/__init__.py b/sphinx_math_dollar/__init__.py
index eadb0bc..14665a6 100644
--- a/sphinx_math_dollar/__init__.py
+++ b/sphinx_math_dollar/__init__.py
@@ -3,6 +3,5 @@
 
 __all__ = ['split_dollars', 'setup', 'NODE_BLACKLIST']
 
-from ._version import get_versions
-__version__ = get_versions()['version']
-del get_versions
+from . import _version
+__version__ = _version.get_versions()['version']
diff --git a/sphinx_math_dollar/_version.py b/sphinx_math_dollar/_version.py
index a692725..4b5816a 100644
--- a/sphinx_math_dollar/_version.py
+++ b/sphinx_math_dollar/_version.py
@@ -6,7 +6,7 @@
 # that just contains the computed version number.
 
 # This file is released into the public domain. Generated by
-# versioneer-0.18 (https://github.com/warner/python-versioneer)
+# versioneer-0.21 (https://github.com/python-versioneer/python-versioneer)
 
 """Git implementation of _version.py."""
 
@@ -15,6 +15,7 @@
 import re
 import subprocess
 import sys
+from typing import Callable, Dict
 
 
 def get_keywords():
@@ -52,12 +53,12 @@ class NotThisMethod(Exception):
     """Exception raised if a method is not valid for the current scenario."""
 
 
-LONG_VERSION_PY = {}
-HANDLERS = {}
+LONG_VERSION_PY: Dict[str, str] = {}
+HANDLERS: Dict[str, Dict[str, Callable]] = {}
 
 
 def register_vcs_handler(vcs, method):  # decorator
-    """Decorator to mark a method as the handler for a particular VCS."""
+    """Create decorator to mark a method as the handler of a VCS."""
     def decorate(f):
         """Store f in HANDLERS[vcs][method]."""
         if vcs not in HANDLERS:
@@ -71,17 +72,17 @@ def run_command(commands, args, cwd=None, verbose=False, hide_stderr=False,
                 env=None):
     """Call the given command(s)."""
     assert isinstance(commands, list)
-    p = None
-    for c in commands:
+    process = None
+    for command in commands:
         try:
-            dispcmd = str([c] + args)
+            dispcmd = str([command] + args)
             # remember shell=False, so use git.cmd on windows, not just git
-            p = subprocess.Popen([c] + args, cwd=cwd, env=env,
-                                 stdout=subprocess.PIPE,
-                                 stderr=(subprocess.PIPE if hide_stderr
-                                         else None))
+            process = subprocess.Popen([command] + args, cwd=cwd, env=env,
+                                       stdout=subprocess.PIPE,
+                                       stderr=(subprocess.PIPE if hide_stderr
+                                               else None))
             break
-        except EnvironmentError:
+        except OSError:
             e = sys.exc_info()[1]
             if e.errno == errno.ENOENT:
                 continue
@@ -93,15 +94,13 @@ def run_command(commands, args, cwd=None, verbose=False, hide_stderr=False,
         if verbose:
             print("unable to find command, tried %s" % (commands,))
         return None, None
-    stdout = p.communicate()[0].strip()
-    if sys.version_info[0] >= 3:
-        stdout = stdout.decode()
-    if p.returncode != 0:
+    stdout = process.communicate()[0].strip().decode()
+    if process.returncode != 0:
         if verbose:
             print("unable to run %s (error)" % dispcmd)
             print("stdout was %s" % stdout)
-        return None, p.returncode
-    return stdout, p.returncode
+        return None, process.returncode
+    return stdout, process.returncode
 
 
 def versions_from_parentdir(parentdir_prefix, root, verbose):
@@ -113,15 +112,14 @@ def versions_from_parentdir(parentdir_prefix, root, verbose):
     """
     rootdirs = []
 
-    for i in range(3):
+    for _ in range(3):
         dirname = os.path.basename(root)
         if dirname.startswith(parentdir_prefix):
             return {"version": dirname[len(parentdir_prefix):],
                     "full-revisionid": None,
                     "dirty": False, "error": None, "date": None}
-        else:
-            rootdirs.append(root)
-            root = os.path.dirname(root)  # up a level
+        rootdirs.append(root)
+        root = os.path.dirname(root)  # up a level
 
     if verbose:
         print("Tried directories %s but none started with prefix %s" %
@@ -138,22 +136,21 @@ def git_get_keywords(versionfile_abs):
     # _version.py.
     keywords = {}
     try:
-        f = open(versionfile_abs, "r")
-        for line in f.readlines():
-            if line.strip().startswith("git_refnames ="):
-                mo = re.search(r'=\s*"(.*)"', line)
-                if mo:
-                    keywords["refnames"] = mo.group(1)
-            if line.strip().startswith("git_full ="):
-                mo = re.search(r'=\s*"(.*)"', line)
-                if mo:
-                    keywords["full"] = mo.group(1)
-            if line.strip().startswith("git_date ="):
-                mo = re.search(r'=\s*"(.*)"', line)
-                if mo:
-                    keywords["date"] = mo.group(1)
-        f.close()
-    except EnvironmentError:
+        with open(versionfile_abs, "r") as fobj:
+            for line in fobj:
+                if line.strip().startswith("git_refnames ="):
+                    mo = re.search(r'=\s*"(.*)"', line)
+                    if mo:
+                        keywords["refnames"] = mo.group(1)
+                if line.strip().startswith("git_full ="):
+                    mo = re.search(r'=\s*"(.*)"', line)
+                    if mo:
+                        keywords["full"] = mo.group(1)
+                if line.strip().startswith("git_date ="):
+                    mo = re.search(r'=\s*"(.*)"', line)
+                    if mo:
+                        keywords["date"] = mo.group(1)
+    except OSError:
         pass
     return keywords
 
@@ -161,10 +158,14 @@ def git_get_keywords(versionfile_abs):
 @register_vcs_handler("git", "keywords")
 def git_versions_from_keywords(keywords, tag_prefix, verbose):
     """Get version information from git keywords."""
-    if not keywords:
-        raise NotThisMethod("no keywords at all, weird")
+    if "refnames" not in keywords:
+        raise NotThisMethod("Short version file found")
     date = keywords.get("date")
     if date is not None:
+        # Use only the last line.  Previous lines may contain GPG signature
+        # information.
+        date = date.splitlines()[-1]
+
         # git-2.2.0 added "%cI", which expands to an ISO-8601 -compliant
         # datestamp. However we prefer "%ci" (which expands to an "ISO-8601
         # -like" string, which we must then edit to make compliant), because
@@ -177,11 +178,11 @@ def git_versions_from_keywords(keywords, tag_prefix, verbose):
         if verbose:
             print("keywords are unexpanded, not using")
         raise NotThisMethod("unexpanded keywords, not a git-archive tarball")
-    refs = set([r.strip() for r in refnames.strip("()").split(",")])
+    refs = {r.strip() for r in refnames.strip("()").split(",")}
     # starting in git-1.8.3, tags are listed as "tag: foo-1.0" instead of
     # just "foo-1.0". If we see a "tag: " prefix, prefer those.
     TAG = "tag: "
-    tags = set([r[len(TAG):] for r in refs if r.startswith(TAG)])
+    tags = {r[len(TAG):] for r in refs if r.startswith(TAG)}
     if not tags:
         # Either we're using git < 1.8.3, or there really are no tags. We use
         # a heuristic: assume all version tags have a digit. The old git %d
@@ -190,7 +191,7 @@ def git_versions_from_keywords(keywords, tag_prefix, verbose):
         # between branches and tags. By ignoring refnames without digits, we
         # filter out many common branch names like "release" and
         # "stabilization", as well as "HEAD" and "master".
-        tags = set([r for r in refs if re.search(r'\d', r)])
+        tags = {r for r in refs if re.search(r'\d', r)}
         if verbose:
             print("discarding '%s', no digits" % ",".join(refs - tags))
     if verbose:
@@ -199,6 +200,11 @@ def git_versions_from_keywords(keywords, tag_prefix, verbose):
         # sorting will prefer e.g. "2.0" over "2.0rc1"
         if ref.startswith(tag_prefix):
             r = ref[len(tag_prefix):]
+            # Filter out refs that exactly match prefix or that don't start
+            # with a number once the prefix is stripped (mostly a concern
+            # when prefix is '')
+            if not re.match(r'\d', r):
+                continue
             if verbose:
                 print("picking %s" % r)
             return {"version": r,
@@ -214,7 +220,7 @@ def git_versions_from_keywords(keywords, tag_prefix, verbose):
 
 
 @register_vcs_handler("git", "pieces_from_vcs")
-def git_pieces_from_vcs(tag_prefix, root, verbose, run_command=run_command):
+def git_pieces_from_vcs(tag_prefix, root, verbose, runner=run_command):
     """Get version from 'git describe' in the root of the source tree.
 
     This only gets called if the git-archive 'subst' keywords were *not*
@@ -222,11 +228,13 @@ def git_pieces_from_vcs(tag_prefix, root, verbose, run_command=run_command):
     version string, meaning we're inside a checked out source tree.
     """
     GITS = ["git"]
+    TAG_PREFIX_REGEX = "*"
     if sys.platform == "win32":
         GITS = ["git.cmd", "git.exe"]
+        TAG_PREFIX_REGEX = r"\*"
 
-    out, rc = run_command(GITS, ["rev-parse", "--git-dir"], cwd=root,
-                          hide_stderr=True)
+    _, rc = runner(GITS, ["rev-parse", "--git-dir"], cwd=root,
+                   hide_stderr=True)
     if rc != 0:
         if verbose:
             print("Directory %s not under git control" % root)
@@ -234,15 +242,16 @@ def git_pieces_from_vcs(tag_prefix, root, verbose, run_command=run_command):
 
     # if there is a tag matching tag_prefix, this yields TAG-NUM-gHEX[-dirty]
     # if there isn't one, this yields HEX[-dirty] (no NUM)
-    describe_out, rc = run_command(GITS, ["describe", "--tags", "--dirty",
-                                          "--always", "--long",
-                                          "--match", "%s*" % tag_prefix],
-                                   cwd=root)
+    describe_out, rc = runner(GITS, ["describe", "--tags", "--dirty",
+                                     "--always", "--long",
+                                     "--match",
+                                     "%s%s" % (tag_prefix, TAG_PREFIX_REGEX)],
+                              cwd=root)
     # --long was added in git-1.5.5
     if describe_out is None:
         raise NotThisMethod("'git describe' failed")
     describe_out = describe_out.strip()
-    full_out, rc = run_command(GITS, ["rev-parse", "HEAD"], cwd=root)
+    full_out, rc = runner(GITS, ["rev-parse", "HEAD"], cwd=root)
     if full_out is None:
         raise NotThisMethod("'git rev-parse' failed")
     full_out = full_out.strip()
@@ -252,6 +261,39 @@ def git_pieces_from_vcs(tag_prefix, root, verbose, run_command=run_command):
     pieces["short"] = full_out[:7]  # maybe improved later
     pieces["error"] = None
 
+    branch_name, rc = runner(GITS, ["rev-parse", "--abbrev-ref", "HEAD"],
+                             cwd=root)
+    # --abbrev-ref was added in git-1.6.3
+    if rc != 0 or branch_name is None:
+        raise NotThisMethod("'git rev-parse --abbrev-ref' returned error")
+    branch_name = branch_name.strip()
+
+    if branch_name == "HEAD":
+        # If we aren't exactly on a branch, pick a branch which represents
+        # the current commit. If all else fails, we are on a branchless
+        # commit.
+        branches, rc = runner(GITS, ["branch", "--contains"], cwd=root)
+        # --contains was added in git-1.5.4
+        if rc != 0 or branches is None:
+            raise NotThisMethod("'git branch --contains' returned error")
+        branches = branches.split("\n")
+
+        # Remove the first line if we're running detached
+        if "(" in branches[0]:
+            branches.pop(0)
+
+        # Strip off the leading "* " from the list of branches.
+        branches = [branch[2:] for branch in branches]
+        if "master" in branches:
+            branch_name = "master"
+        elif not branches:
+            branch_name = None
+        else:
+            # Pick the first branch that is returned. Good or bad.
+            branch_name = branches[0]
+
+    pieces["branch"] = branch_name
+
     # parse describe_out. It will be like TAG-NUM-gHEX[-dirty] or HEX[-dirty]
     # TAG might have hyphens.
     git_describe = describe_out
@@ -268,7 +310,7 @@ def git_pieces_from_vcs(tag_prefix, root, verbose, run_command=run_command):
         # TAG-NUM-gHEX
         mo = re.search(r'^(.+)-(\d+)-g([0-9a-f]+)$', git_describe)
         if not mo:
-            # unparseable. Maybe git-describe is misbehaving?
+            # unparsable. Maybe git-describe is misbehaving?
             pieces["error"] = ("unable to parse git-describe output: '%s'"
                                % describe_out)
             return pieces
@@ -293,13 +335,14 @@ def git_pieces_from_vcs(tag_prefix, root, verbose, run_command=run_command):
     else:
         # HEX: no tags
         pieces["closest-tag"] = None
-        count_out, rc = run_command(GITS, ["rev-list", "HEAD", "--count"],
-                                    cwd=root)
+        count_out, rc = runner(GITS, ["rev-list", "HEAD", "--count"], cwd=root)
         pieces["distance"] = int(count_out)  # total number of commits
 
     # commit date: see ISO-8601 comment in git_versions_from_keywords()
-    date = run_command(GITS, ["show", "-s", "--format=%ci", "HEAD"],
-                       cwd=root)[0].strip()
+    date = runner(GITS, ["show", "-s", "--format=%ci", "HEAD"], cwd=root)[0].strip()
+    # Use only the last line.  Previous lines may contain GPG signature
+    # information.
+    date = date.splitlines()[-1]
     pieces["date"] = date.strip().replace(" ", "T", 1).replace(" ", "", 1)
 
     return pieces
@@ -337,19 +380,67 @@ def render_pep440(pieces):
     return rendered
 
 
-def render_pep440_pre(pieces):
-    """TAG[.post.devDISTANCE] -- No -dirty.
+def render_pep440_branch(pieces):
+    """TAG[[.dev0]+DISTANCE.gHEX[.dirty]] .
+
+    The ".dev0" means not master branch. Note that .dev0 sorts backwards
+    (a feature branch will appear "older" than the master branch).
 
     Exceptions:
-    1: no tags. 0.post.devDISTANCE
+    1: no tags. 0[.dev0]+untagged.DISTANCE.gHEX[.dirty]
     """
     if pieces["closest-tag"]:
         rendered = pieces["closest-tag"]
+        if pieces["distance"] or pieces["dirty"]:
+            if pieces["branch"] != "master":
+                rendered += ".dev0"
+            rendered += plus_or_dot(pieces)
+            rendered += "%d.g%s" % (pieces["distance"], pieces["short"])
+            if pieces["dirty"]:
+                rendered += ".dirty"
+    else:
+        # exception #1
+        rendered = "0"
+        if pieces["branch"] != "master":
+            rendered += ".dev0"
+        rendered += "+untagged.%d.g%s" % (pieces["distance"],
+                                          pieces["short"])
+        if pieces["dirty"]:
+            rendered += ".dirty"
+    return rendered
+
+
+def pep440_split_post(ver):
+    """Split pep440 version string at the post-release segment.
+
+    Returns the release segments before the post-release and the
+    post-release version number (or -1 if no post-release segment is present).
+    """
+    vc = str.split(ver, ".post")
+    return vc[0], int(vc[1] or 0) if len(vc) == 2 else None
+
+
+def render_pep440_pre(pieces):
+    """TAG[.postN.devDISTANCE] -- No -dirty.
+
+    Exceptions:
+    1: no tags. 0.post0.devDISTANCE
+    """
+    if pieces["closest-tag"]:
         if pieces["distance"]:
-            rendered += ".post.dev%d" % pieces["distance"]
+            # update the post release segment
+            tag_version, post_version = pep440_split_post(pieces["closest-tag"])
+            rendered = tag_version
+            if post_version is not None:
+                rendered += ".post%d.dev%d" % (post_version+1, pieces["distance"])
+            else:
+                rendered += ".post0.dev%d" % (pieces["distance"])
+        else:
+            # no commits, use the tag as the version
+            rendered = pieces["closest-tag"]
     else:
         # exception #1
-        rendered = "0.post.dev%d" % pieces["distance"]
+        rendered = "0.post0.dev%d" % pieces["distance"]
     return rendered
 
 
@@ -380,12 +471,41 @@ def render_pep440_post(pieces):
     return rendered
 
 
+def render_pep440_post_branch(pieces):
+    """TAG[.postDISTANCE[.dev0]+gHEX[.dirty]] .
+
+    The ".dev0" means not master branch.
+
+    Exceptions:
+    1: no tags. 0.postDISTANCE[.dev0]+gHEX[.dirty]
+    """
+    if pieces["closest-tag"]:
+        rendered = pieces["closest-tag"]
+        if pieces["distance"] or pieces["dirty"]:
+            rendered += ".post%d" % pieces["distance"]
+            if pieces["branch"] != "master":
+                rendered += ".dev0"
+            rendered += plus_or_dot(pieces)
+            rendered += "g%s" % pieces["short"]
+            if pieces["dirty"]:
+                rendered += ".dirty"
+    else:
+        # exception #1
+        rendered = "0.post%d" % pieces["distance"]
+        if pieces["branch"] != "master":
+            rendered += ".dev0"
+        rendered += "+g%s" % pieces["short"]
+        if pieces["dirty"]:
+            rendered += ".dirty"
+    return rendered
+
+
 def render_pep440_old(pieces):
     """TAG[.postDISTANCE[.dev0]] .
 
     The ".dev0" means dirty.
 
-    Eexceptions:
+    Exceptions:
     1: no tags. 0.postDISTANCE[.dev0]
     """
     if pieces["closest-tag"]:
@@ -456,10 +576,14 @@ def render(pieces, style):
 
     if style == "pep440":
         rendered = render_pep440(pieces)
+    elif style == "pep440-branch":
+        rendered = render_pep440_branch(pieces)
     elif style == "pep440-pre":
         rendered = render_pep440_pre(pieces)
     elif style == "pep440-post":
         rendered = render_pep440_post(pieces)
+    elif style == "pep440-post-branch":
+        rendered = render_pep440_post_branch(pieces)
     elif style == "pep440-old":
         rendered = render_pep440_old(pieces)
     elif style == "git-describe":
@@ -495,7 +619,7 @@ def get_versions():
         # versionfile_source is the relative path from the top of the source
         # tree (where the .git directory might live) to this file. Invert
         # this to find the root from __file__.
-        for i in cfg.versionfile_source.split('/'):
+        for _ in cfg.versionfile_source.split('/'):
             root = os.path.dirname(root)
     except NameError:
         return {"version": "0+unknown", "full-revisionid": None,
diff --git a/sphinx_math_dollar/extension.py b/sphinx_math_dollar/extension.py
index 3fbf01e..85e9705 100644
--- a/sphinx_math_dollar/extension.py
+++ b/sphinx_math_dollar/extension.py
@@ -1,4 +1,3 @@
-from __future__ import print_function
 import os
 import sys
 
diff --git a/versioneer.py b/versioneer.py
index 64fea1c..b4cd1d6 100644
--- a/versioneer.py
+++ b/versioneer.py
@@ -1,5 +1,5 @@
 
-# Version: 0.18
+# Version: 0.21
 
 """The Versioneer - like a rocketeer, but for versions.
 
@@ -7,16 +7,12 @@
 ==============
 
 * like a rocketeer, but for versions!
-* https://github.com/warner/python-versioneer
+* https://github.com/python-versioneer/python-versioneer
 * Brian Warner
 * License: Public Domain
-* Compatible With: python2.6, 2.7, 3.2, 3.3, 3.4, 3.5, 3.6, and pypy
-* [![Latest Version]
-(https://pypip.in/version/versioneer/badge.svg?style=flat)
-](https://pypi.python.org/pypi/versioneer/)
-* [![Build Status]
-(https://travis-ci.org/warner/python-versioneer.png?branch=master)
-](https://travis-ci.org/warner/python-versioneer)
+* Compatible with: Python 3.6, 3.7, 3.8, 3.9 and pypy3
+* [![Latest Version][pypi-image]][pypi-url]
+* [![Build Status][travis-image]][travis-url]
 
 This is a tool for managing a recorded version number in distutils-based
 python projects. The goal is to remove the tedious and error-prone "update
@@ -27,9 +23,10 @@
 
 ## Quick Install
 
-* `pip install versioneer` to somewhere to your $PATH
-* add a `[versioneer]` section to your setup.cfg (see below)
+* `pip install versioneer` to somewhere in your $PATH
+* add a `[versioneer]` section to your setup.cfg (see [Install](INSTALL.md))
 * run `versioneer install` in your source tree, commit the results
+* Verify version information with `python setup.py version`
 
 ## Version Identifiers
 
@@ -61,7 +58,7 @@
 for example `git describe --tags --dirty --always` reports things like
 "0.7-1-g574ab98-dirty" to indicate that the checkout is one revision past the
 0.7 tag, has a unique revision id of "574ab98", and is "dirty" (it has
-uncommitted changes.
+uncommitted changes).
 
 The version identifier is used for multiple purposes:
 
@@ -166,7 +163,7 @@
 
 Some situations are known to cause problems for Versioneer. This details the
 most significant ones. More can be found on Github
-[issues page](https://github.com/warner/python-versioneer/issues).
+[issues page](https://github.com/python-versioneer/python-versioneer/issues).
 
 ### Subprojects
 
@@ -180,7 +177,7 @@
   `setup.cfg`, and `tox.ini`. Projects like these produce multiple PyPI
   distributions (and upload multiple independently-installable tarballs).
 * Source trees whose main purpose is to contain a C library, but which also
-  provide bindings to Python (and perhaps other langauges) in subdirectories.
+  provide bindings to Python (and perhaps other languages) in subdirectories.
 
 Versioneer will look for `.git` in parent directories, and most operations
 should get the right version string. However `pip` and `setuptools` have bugs
@@ -194,9 +191,9 @@
 Pip-8.1.1 is known to have this problem, but hopefully it will get fixed in
 some later version.
 
-[Bug #38](https://github.com/warner/python-versioneer/issues/38) is tracking
+[Bug #38](https://github.com/python-versioneer/python-versioneer/issues/38) is tracking
 this issue. The discussion in
-[PR #61](https://github.com/warner/python-versioneer/pull/61) describes the
+[PR #61](https://github.com/python-versioneer/python-versioneer/pull/61) describes the
 issue from the Versioneer side in more detail.
 [pip PR#3176](https://github.com/pypa/pip/pull/3176) and
 [pip PR#3615](https://github.com/pypa/pip/pull/3615) contain work to improve
@@ -224,22 +221,10 @@
 cause egg_info to be rebuilt (including `sdist`, `wheel`, and installing into
 a different virtualenv), so this can be surprising.
 
-[Bug #83](https://github.com/warner/python-versioneer/issues/83) describes
+[Bug #83](https://github.com/python-versioneer/python-versioneer/issues/83) describes
 this one, but upgrading to a newer version of setuptools should probably
 resolve it.
 
-### Unicode version strings
-
-While Versioneer works (and is continually tested) with both Python 2 and
-Python 3, it is not entirely consistent with bytes-vs-unicode distinctions.
-Newer releases probably generate unicode version strings on py2. It's not
-clear that this is wrong, but it may be surprising for applications when then
-write these strings to a network connection or include them in bytes-oriented
-APIs like cryptographic checksums.
-
-[Bug #71](https://github.com/warner/python-versioneer/issues/71) investigates
-this question.
-
 
 ## Updating Versioneer
 
@@ -265,6 +250,14 @@
 direction and include code from all supported VCS systems, reducing the
 number of intermediate scripts.
 
+## Similar projects
+
+* [setuptools_scm](https://github.com/pypa/setuptools_scm/) - a non-vendored build-time
+  dependency
+* [minver](https://github.com/jbweston/miniver) - a lightweight reimplementation of
+  versioneer
+* [versioningit](https://github.com/jwodder/versioningit) - a PEP 518-based setuptools
+  plugin
 
 ## License
 
@@ -274,19 +267,27 @@
 Dedication" license (CC0-1.0), as described in
 https://creativecommons.org/publicdomain/zero/1.0/ .
 
+[pypi-image]: https://img.shields.io/pypi/v/versioneer.svg
+[pypi-url]: https://pypi.python.org/pypi/versioneer/
+[travis-image]:
+https://img.shields.io/travis/com/python-versioneer/python-versioneer.svg
+[travis-url]: https://travis-ci.com/github/python-versioneer/python-versioneer
+
 """
+# pylint:disable=invalid-name,import-outside-toplevel,missing-function-docstring
+# pylint:disable=missing-class-docstring,too-many-branches,too-many-statements
+# pylint:disable=raise-missing-from,too-many-lines,too-many-locals,import-error
+# pylint:disable=too-few-public-methods,redefined-outer-name,consider-using-with
+# pylint:disable=attribute-defined-outside-init,too-many-arguments
 
-from __future__ import print_function
-try:
-    import configparser
-except ImportError:
-    import ConfigParser as configparser
+import configparser
 import errno
 import json
 import os
 import re
 import subprocess
 import sys
+from typing import Callable, Dict
 
 
 class VersioneerConfig:
@@ -321,12 +322,12 @@ def get_root():
         # module-import table will cache the first one. So we can't use
         # os.path.dirname(__file__), as that will find whichever
         # versioneer.py was first imported, even in later projects.
-        me = os.path.realpath(os.path.abspath(__file__))
-        me_dir = os.path.normcase(os.path.splitext(me)[0])
+        my_path = os.path.realpath(os.path.abspath(__file__))
+        me_dir = os.path.normcase(os.path.splitext(my_path)[0])
         vsr_dir = os.path.normcase(os.path.splitext(versioneer_py)[0])
         if me_dir != vsr_dir:
             print("Warning: build in %s is using versioneer.py from %s"
-                  % (os.path.dirname(me), versioneer_py))
+                  % (os.path.dirname(my_path), versioneer_py))
     except NameError:
         pass
     return root
@@ -334,30 +335,29 @@ def get_root():
 
 def get_config_from_root(root):
     """Read the project setup.cfg file to determine Versioneer config."""
-    # This might raise EnvironmentError (if setup.cfg is missing), or
+    # This might raise OSError (if setup.cfg is missing), or
     # configparser.NoSectionError (if it lacks a [versioneer] section), or
     # configparser.NoOptionError (if it lacks "VCS="). See the docstring at
     # the top of versioneer.py for instructions on writing your setup.cfg .
     setup_cfg = os.path.join(root, "setup.cfg")
-    parser = configparser.SafeConfigParser()
-    with open(setup_cfg, "r") as f:
-        parser.readfp(f)
+    parser = configparser.ConfigParser()
+    with open(setup_cfg, "r") as cfg_file:
+        parser.read_file(cfg_file)
     VCS = parser.get("versioneer", "VCS")  # mandatory
 
-    def get(parser, name):
-        if parser.has_option("versioneer", name):
-            return parser.get("versioneer", name)
-        return None
+    # Dict-like interface for non-mandatory entries
+    section = parser["versioneer"]
+
     cfg = VersioneerConfig()
     cfg.VCS = VCS
-    cfg.style = get(parser, "style") or ""
-    cfg.versionfile_source = get(parser, "versionfile_source")
-    cfg.versionfile_build = get(parser, "versionfile_build")
-    cfg.tag_prefix = get(parser, "tag_prefix")
+    cfg.style = section.get("style", "")
+    cfg.versionfile_source = section.get("versionfile_source")
+    cfg.versionfile_build = section.get("versionfile_build")
+    cfg.tag_prefix = section.get("tag_prefix")
     if cfg.tag_prefix in ("''", '""'):
         cfg.tag_prefix = ""
-    cfg.parentdir_prefix = get(parser, "parentdir_prefix")
-    cfg.verbose = get(parser, "verbose")
+    cfg.parentdir_prefix = section.get("parentdir_prefix")
+    cfg.verbose = section.get("verbose")
     return cfg
 
 
@@ -366,17 +366,15 @@ class NotThisMethod(Exception):
 
 
 # these dictionaries contain VCS-specific tools
-LONG_VERSION_PY = {}
-HANDLERS = {}
+LONG_VERSION_PY: Dict[str, str] = {}
+HANDLERS: Dict[str, Dict[str, Callable]] = {}
 
 
 def register_vcs_handler(vcs, method):  # decorator
-    """Decorator to mark a method as the handler for a particular VCS."""
+    """Create decorator to mark a method as the handler of a VCS."""
     def decorate(f):
         """Store f in HANDLERS[vcs][method]."""
-        if vcs not in HANDLERS:
-            HANDLERS[vcs] = {}
-        HANDLERS[vcs][method] = f
+        HANDLERS.setdefault(vcs, {})[method] = f
         return f
     return decorate
 
@@ -385,17 +383,17 @@ def run_command(commands, args, cwd=None, verbose=False, hide_stderr=False,
                 env=None):
     """Call the given command(s)."""
     assert isinstance(commands, list)
-    p = None
-    for c in commands:
+    process = None
+    for command in commands:
         try:
-            dispcmd = str([c] + args)
+            dispcmd = str([command] + args)
             # remember shell=False, so use git.cmd on windows, not just git
-            p = subprocess.Popen([c] + args, cwd=cwd, env=env,
-                                 stdout=subprocess.PIPE,
-                                 stderr=(subprocess.PIPE if hide_stderr
-                                         else None))
+            process = subprocess.Popen([command] + args, cwd=cwd, env=env,
+                                       stdout=subprocess.PIPE,
+                                       stderr=(subprocess.PIPE if hide_stderr
+                                               else None))
             break
-        except EnvironmentError:
+        except OSError:
             e = sys.exc_info()[1]
             if e.errno == errno.ENOENT:
                 continue
@@ -407,18 +405,16 @@ def run_command(commands, args, cwd=None, verbose=False, hide_stderr=False,
         if verbose:
             print("unable to find command, tried %s" % (commands,))
         return None, None
-    stdout = p.communicate()[0].strip()
-    if sys.version_info[0] >= 3:
-        stdout = stdout.decode()
-    if p.returncode != 0:
+    stdout = process.communicate()[0].strip().decode()
+    if process.returncode != 0:
         if verbose:
             print("unable to run %s (error)" % dispcmd)
             print("stdout was %s" % stdout)
-        return None, p.returncode
-    return stdout, p.returncode
+        return None, process.returncode
+    return stdout, process.returncode
 
 
-LONG_VERSION_PY['git'] = '''
+LONG_VERSION_PY['git'] = r'''
 # This file helps to compute a version number in source trees obtained from
 # git-archive tarball (such as those provided by githubs download-from-tag
 # feature). Distribution tarballs (built by setup.py sdist) and build
@@ -426,7 +422,7 @@ def run_command(commands, args, cwd=None, verbose=False, hide_stderr=False,
 # that just contains the computed version number.
 
 # This file is released into the public domain. Generated by
-# versioneer-0.18 (https://github.com/warner/python-versioneer)
+# versioneer-0.21 (https://github.com/python-versioneer/python-versioneer)
 
 """Git implementation of _version.py."""
 
@@ -435,6 +431,7 @@ def run_command(commands, args, cwd=None, verbose=False, hide_stderr=False,
 import re
 import subprocess
 import sys
+from typing import Callable, Dict
 
 
 def get_keywords():
@@ -472,12 +469,12 @@ class NotThisMethod(Exception):
     """Exception raised if a method is not valid for the current scenario."""
 
 
-LONG_VERSION_PY = {}
-HANDLERS = {}
+LONG_VERSION_PY: Dict[str, str] = {}
+HANDLERS: Dict[str, Dict[str, Callable]] = {}
 
 
 def register_vcs_handler(vcs, method):  # decorator
-    """Decorator to mark a method as the handler for a particular VCS."""
+    """Create decorator to mark a method as the handler of a VCS."""
     def decorate(f):
         """Store f in HANDLERS[vcs][method]."""
         if vcs not in HANDLERS:
@@ -491,17 +488,17 @@ def run_command(commands, args, cwd=None, verbose=False, hide_stderr=False,
                 env=None):
     """Call the given command(s)."""
     assert isinstance(commands, list)
-    p = None
-    for c in commands:
+    process = None
+    for command in commands:
         try:
-            dispcmd = str([c] + args)
+            dispcmd = str([command] + args)
             # remember shell=False, so use git.cmd on windows, not just git
-            p = subprocess.Popen([c] + args, cwd=cwd, env=env,
-                                 stdout=subprocess.PIPE,
-                                 stderr=(subprocess.PIPE if hide_stderr
-                                         else None))
+            process = subprocess.Popen([command] + args, cwd=cwd, env=env,
+                                       stdout=subprocess.PIPE,
+                                       stderr=(subprocess.PIPE if hide_stderr
+                                               else None))
             break
-        except EnvironmentError:
+        except OSError:
             e = sys.exc_info()[1]
             if e.errno == errno.ENOENT:
                 continue
@@ -513,15 +510,13 @@ def run_command(commands, args, cwd=None, verbose=False, hide_stderr=False,
         if verbose:
             print("unable to find command, tried %%s" %% (commands,))
         return None, None
-    stdout = p.communicate()[0].strip()
-    if sys.version_info[0] >= 3:
-        stdout = stdout.decode()
-    if p.returncode != 0:
+    stdout = process.communicate()[0].strip().decode()
+    if process.returncode != 0:
         if verbose:
             print("unable to run %%s (error)" %% dispcmd)
             print("stdout was %%s" %% stdout)
-        return None, p.returncode
-    return stdout, p.returncode
+        return None, process.returncode
+    return stdout, process.returncode
 
 
 def versions_from_parentdir(parentdir_prefix, root, verbose):
@@ -533,15 +528,14 @@ def versions_from_parentdir(parentdir_prefix, root, verbose):
     """
     rootdirs = []
 
-    for i in range(3):
+    for _ in range(3):
         dirname = os.path.basename(root)
         if dirname.startswith(parentdir_prefix):
             return {"version": dirname[len(parentdir_prefix):],
                     "full-revisionid": None,
                     "dirty": False, "error": None, "date": None}
-        else:
-            rootdirs.append(root)
-            root = os.path.dirname(root)  # up a level
+        rootdirs.append(root)
+        root = os.path.dirname(root)  # up a level
 
     if verbose:
         print("Tried directories %%s but none started with prefix %%s" %%
@@ -558,22 +552,21 @@ def git_get_keywords(versionfile_abs):
     # _version.py.
     keywords = {}
     try:
-        f = open(versionfile_abs, "r")
-        for line in f.readlines():
-            if line.strip().startswith("git_refnames ="):
-                mo = re.search(r'=\s*"(.*)"', line)
-                if mo:
-                    keywords["refnames"] = mo.group(1)
-            if line.strip().startswith("git_full ="):
-                mo = re.search(r'=\s*"(.*)"', line)
-                if mo:
-                    keywords["full"] = mo.group(1)
-            if line.strip().startswith("git_date ="):
-                mo = re.search(r'=\s*"(.*)"', line)
-                if mo:
-                    keywords["date"] = mo.group(1)
-        f.close()
-    except EnvironmentError:
+        with open(versionfile_abs, "r") as fobj:
+            for line in fobj:
+                if line.strip().startswith("git_refnames ="):
+                    mo = re.search(r'=\s*"(.*)"', line)
+                    if mo:
+                        keywords["refnames"] = mo.group(1)
+                if line.strip().startswith("git_full ="):
+                    mo = re.search(r'=\s*"(.*)"', line)
+                    if mo:
+                        keywords["full"] = mo.group(1)
+                if line.strip().startswith("git_date ="):
+                    mo = re.search(r'=\s*"(.*)"', line)
+                    if mo:
+                        keywords["date"] = mo.group(1)
+    except OSError:
         pass
     return keywords
 
@@ -581,10 +574,14 @@ def git_get_keywords(versionfile_abs):
 @register_vcs_handler("git", "keywords")
 def git_versions_from_keywords(keywords, tag_prefix, verbose):
     """Get version information from git keywords."""
-    if not keywords:
-        raise NotThisMethod("no keywords at all, weird")
+    if "refnames" not in keywords:
+        raise NotThisMethod("Short version file found")
     date = keywords.get("date")
     if date is not None:
+        # Use only the last line.  Previous lines may contain GPG signature
+        # information.
+        date = date.splitlines()[-1]
+
         # git-2.2.0 added "%%cI", which expands to an ISO-8601 -compliant
         # datestamp. However we prefer "%%ci" (which expands to an "ISO-8601
         # -like" string, which we must then edit to make compliant), because
@@ -597,11 +594,11 @@ def git_versions_from_keywords(keywords, tag_prefix, verbose):
         if verbose:
             print("keywords are unexpanded, not using")
         raise NotThisMethod("unexpanded keywords, not a git-archive tarball")
-    refs = set([r.strip() for r in refnames.strip("()").split(",")])
+    refs = {r.strip() for r in refnames.strip("()").split(",")}
     # starting in git-1.8.3, tags are listed as "tag: foo-1.0" instead of
     # just "foo-1.0". If we see a "tag: " prefix, prefer those.
     TAG = "tag: "
-    tags = set([r[len(TAG):] for r in refs if r.startswith(TAG)])
+    tags = {r[len(TAG):] for r in refs if r.startswith(TAG)}
     if not tags:
         # Either we're using git < 1.8.3, or there really are no tags. We use
         # a heuristic: assume all version tags have a digit. The old git %%d
@@ -610,7 +607,7 @@ def git_versions_from_keywords(keywords, tag_prefix, verbose):
         # between branches and tags. By ignoring refnames without digits, we
         # filter out many common branch names like "release" and
         # "stabilization", as well as "HEAD" and "master".
-        tags = set([r for r in refs if re.search(r'\d', r)])
+        tags = {r for r in refs if re.search(r'\d', r)}
         if verbose:
             print("discarding '%%s', no digits" %% ",".join(refs - tags))
     if verbose:
@@ -619,6 +616,11 @@ def git_versions_from_keywords(keywords, tag_prefix, verbose):
         # sorting will prefer e.g. "2.0" over "2.0rc1"
         if ref.startswith(tag_prefix):
             r = ref[len(tag_prefix):]
+            # Filter out refs that exactly match prefix or that don't start
+            # with a number once the prefix is stripped (mostly a concern
+            # when prefix is '')
+            if not re.match(r'\d', r):
+                continue
             if verbose:
                 print("picking %%s" %% r)
             return {"version": r,
@@ -634,7 +636,7 @@ def git_versions_from_keywords(keywords, tag_prefix, verbose):
 
 
 @register_vcs_handler("git", "pieces_from_vcs")
-def git_pieces_from_vcs(tag_prefix, root, verbose, run_command=run_command):
+def git_pieces_from_vcs(tag_prefix, root, verbose, runner=run_command):
     """Get version from 'git describe' in the root of the source tree.
 
     This only gets called if the git-archive 'subst' keywords were *not*
@@ -642,11 +644,13 @@ def git_pieces_from_vcs(tag_prefix, root, verbose, run_command=run_command):
     version string, meaning we're inside a checked out source tree.
     """
     GITS = ["git"]
+    TAG_PREFIX_REGEX = "*"
     if sys.platform == "win32":
         GITS = ["git.cmd", "git.exe"]
+        TAG_PREFIX_REGEX = r"\*"
 
-    out, rc = run_command(GITS, ["rev-parse", "--git-dir"], cwd=root,
-                          hide_stderr=True)
+    _, rc = runner(GITS, ["rev-parse", "--git-dir"], cwd=root,
+                   hide_stderr=True)
     if rc != 0:
         if verbose:
             print("Directory %%s not under git control" %% root)
@@ -654,15 +658,16 @@ def git_pieces_from_vcs(tag_prefix, root, verbose, run_command=run_command):
 
     # if there is a tag matching tag_prefix, this yields TAG-NUM-gHEX[-dirty]
     # if there isn't one, this yields HEX[-dirty] (no NUM)
-    describe_out, rc = run_command(GITS, ["describe", "--tags", "--dirty",
-                                          "--always", "--long",
-                                          "--match", "%%s*" %% tag_prefix],
-                                   cwd=root)
+    describe_out, rc = runner(GITS, ["describe", "--tags", "--dirty",
+                                     "--always", "--long",
+                                     "--match",
+                                     "%%s%%s" %% (tag_prefix, TAG_PREFIX_REGEX)],
+                              cwd=root)
     # --long was added in git-1.5.5
     if describe_out is None:
         raise NotThisMethod("'git describe' failed")
     describe_out = describe_out.strip()
-    full_out, rc = run_command(GITS, ["rev-parse", "HEAD"], cwd=root)
+    full_out, rc = runner(GITS, ["rev-parse", "HEAD"], cwd=root)
     if full_out is None:
         raise NotThisMethod("'git rev-parse' failed")
     full_out = full_out.strip()
@@ -672,6 +677,39 @@ def git_pieces_from_vcs(tag_prefix, root, verbose, run_command=run_command):
     pieces["short"] = full_out[:7]  # maybe improved later
     pieces["error"] = None
 
+    branch_name, rc = runner(GITS, ["rev-parse", "--abbrev-ref", "HEAD"],
+                             cwd=root)
+    # --abbrev-ref was added in git-1.6.3
+    if rc != 0 or branch_name is None:
+        raise NotThisMethod("'git rev-parse --abbrev-ref' returned error")
+    branch_name = branch_name.strip()
+
+    if branch_name == "HEAD":
+        # If we aren't exactly on a branch, pick a branch which represents
+        # the current commit. If all else fails, we are on a branchless
+        # commit.
+        branches, rc = runner(GITS, ["branch", "--contains"], cwd=root)
+        # --contains was added in git-1.5.4
+        if rc != 0 or branches is None:
+            raise NotThisMethod("'git branch --contains' returned error")
+        branches = branches.split("\n")
+
+        # Remove the first line if we're running detached
+        if "(" in branches[0]:
+            branches.pop(0)
+
+        # Strip off the leading "* " from the list of branches.
+        branches = [branch[2:] for branch in branches]
+        if "master" in branches:
+            branch_name = "master"
+        elif not branches:
+            branch_name = None
+        else:
+            # Pick the first branch that is returned. Good or bad.
+            branch_name = branches[0]
+
+    pieces["branch"] = branch_name
+
     # parse describe_out. It will be like TAG-NUM-gHEX[-dirty] or HEX[-dirty]
     # TAG might have hyphens.
     git_describe = describe_out
@@ -688,7 +726,7 @@ def git_pieces_from_vcs(tag_prefix, root, verbose, run_command=run_command):
         # TAG-NUM-gHEX
         mo = re.search(r'^(.+)-(\d+)-g([0-9a-f]+)$', git_describe)
         if not mo:
-            # unparseable. Maybe git-describe is misbehaving?
+            # unparsable. Maybe git-describe is misbehaving?
             pieces["error"] = ("unable to parse git-describe output: '%%s'"
                                %% describe_out)
             return pieces
@@ -713,13 +751,14 @@ def git_pieces_from_vcs(tag_prefix, root, verbose, run_command=run_command):
     else:
         # HEX: no tags
         pieces["closest-tag"] = None
-        count_out, rc = run_command(GITS, ["rev-list", "HEAD", "--count"],
-                                    cwd=root)
+        count_out, rc = runner(GITS, ["rev-list", "HEAD", "--count"], cwd=root)
         pieces["distance"] = int(count_out)  # total number of commits
 
     # commit date: see ISO-8601 comment in git_versions_from_keywords()
-    date = run_command(GITS, ["show", "-s", "--format=%%ci", "HEAD"],
-                       cwd=root)[0].strip()
+    date = runner(GITS, ["show", "-s", "--format=%%ci", "HEAD"], cwd=root)[0].strip()
+    # Use only the last line.  Previous lines may contain GPG signature
+    # information.
+    date = date.splitlines()[-1]
     pieces["date"] = date.strip().replace(" ", "T", 1).replace(" ", "", 1)
 
     return pieces
@@ -757,19 +796,67 @@ def render_pep440(pieces):
     return rendered
 
 
-def render_pep440_pre(pieces):
-    """TAG[.post.devDISTANCE] -- No -dirty.
+def render_pep440_branch(pieces):
+    """TAG[[.dev0]+DISTANCE.gHEX[.dirty]] .
+
+    The ".dev0" means not master branch. Note that .dev0 sorts backwards
+    (a feature branch will appear "older" than the master branch).
 
     Exceptions:
-    1: no tags. 0.post.devDISTANCE
+    1: no tags. 0[.dev0]+untagged.DISTANCE.gHEX[.dirty]
     """
     if pieces["closest-tag"]:
         rendered = pieces["closest-tag"]
+        if pieces["distance"] or pieces["dirty"]:
+            if pieces["branch"] != "master":
+                rendered += ".dev0"
+            rendered += plus_or_dot(pieces)
+            rendered += "%%d.g%%s" %% (pieces["distance"], pieces["short"])
+            if pieces["dirty"]:
+                rendered += ".dirty"
+    else:
+        # exception #1
+        rendered = "0"
+        if pieces["branch"] != "master":
+            rendered += ".dev0"
+        rendered += "+untagged.%%d.g%%s" %% (pieces["distance"],
+                                          pieces["short"])
+        if pieces["dirty"]:
+            rendered += ".dirty"
+    return rendered
+
+
+def pep440_split_post(ver):
+    """Split pep440 version string at the post-release segment.
+
+    Returns the release segments before the post-release and the
+    post-release version number (or -1 if no post-release segment is present).
+    """
+    vc = str.split(ver, ".post")
+    return vc[0], int(vc[1] or 0) if len(vc) == 2 else None
+
+
+def render_pep440_pre(pieces):
+    """TAG[.postN.devDISTANCE] -- No -dirty.
+
+    Exceptions:
+    1: no tags. 0.post0.devDISTANCE
+    """
+    if pieces["closest-tag"]:
         if pieces["distance"]:
-            rendered += ".post.dev%%d" %% pieces["distance"]
+            # update the post release segment
+            tag_version, post_version = pep440_split_post(pieces["closest-tag"])
+            rendered = tag_version
+            if post_version is not None:
+                rendered += ".post%%d.dev%%d" %% (post_version+1, pieces["distance"])
+            else:
+                rendered += ".post0.dev%%d" %% (pieces["distance"])
+        else:
+            # no commits, use the tag as the version
+            rendered = pieces["closest-tag"]
     else:
         # exception #1
-        rendered = "0.post.dev%%d" %% pieces["distance"]
+        rendered = "0.post0.dev%%d" %% pieces["distance"]
     return rendered
 
 
@@ -800,12 +887,41 @@ def render_pep440_post(pieces):
     return rendered
 
 
+def render_pep440_post_branch(pieces):
+    """TAG[.postDISTANCE[.dev0]+gHEX[.dirty]] .
+
+    The ".dev0" means not master branch.
+
+    Exceptions:
+    1: no tags. 0.postDISTANCE[.dev0]+gHEX[.dirty]
+    """
+    if pieces["closest-tag"]:
+        rendered = pieces["closest-tag"]
+        if pieces["distance"] or pieces["dirty"]:
+            rendered += ".post%%d" %% pieces["distance"]
+            if pieces["branch"] != "master":
+                rendered += ".dev0"
+            rendered += plus_or_dot(pieces)
+            rendered += "g%%s" %% pieces["short"]
+            if pieces["dirty"]:
+                rendered += ".dirty"
+    else:
+        # exception #1
+        rendered = "0.post%%d" %% pieces["distance"]
+        if pieces["branch"] != "master":
+            rendered += ".dev0"
+        rendered += "+g%%s" %% pieces["short"]
+        if pieces["dirty"]:
+            rendered += ".dirty"
+    return rendered
+
+
 def render_pep440_old(pieces):
     """TAG[.postDISTANCE[.dev0]] .
 
     The ".dev0" means dirty.
 
-    Eexceptions:
+    Exceptions:
     1: no tags. 0.postDISTANCE[.dev0]
     """
     if pieces["closest-tag"]:
@@ -876,10 +992,14 @@ def render(pieces, style):
 
     if style == "pep440":
         rendered = render_pep440(pieces)
+    elif style == "pep440-branch":
+        rendered = render_pep440_branch(pieces)
     elif style == "pep440-pre":
         rendered = render_pep440_pre(pieces)
     elif style == "pep440-post":
         rendered = render_pep440_post(pieces)
+    elif style == "pep440-post-branch":
+        rendered = render_pep440_post_branch(pieces)
     elif style == "pep440-old":
         rendered = render_pep440_old(pieces)
     elif style == "git-describe":
@@ -915,7 +1035,7 @@ def get_versions():
         # versionfile_source is the relative path from the top of the source
         # tree (where the .git directory might live) to this file. Invert
         # this to find the root from __file__.
-        for i in cfg.versionfile_source.split('/'):
+        for _ in cfg.versionfile_source.split('/'):
             root = os.path.dirname(root)
     except NameError:
         return {"version": "0+unknown", "full-revisionid": None,
@@ -950,22 +1070,21 @@ def git_get_keywords(versionfile_abs):
     # _version.py.
     keywords = {}
     try:
-        f = open(versionfile_abs, "r")
-        for line in f.readlines():
-            if line.strip().startswith("git_refnames ="):
-                mo = re.search(r'=\s*"(.*)"', line)
-                if mo:
-                    keywords["refnames"] = mo.group(1)
-            if line.strip().startswith("git_full ="):
-                mo = re.search(r'=\s*"(.*)"', line)
-                if mo:
-                    keywords["full"] = mo.group(1)
-            if line.strip().startswith("git_date ="):
-                mo = re.search(r'=\s*"(.*)"', line)
-                if mo:
-                    keywords["date"] = mo.group(1)
-        f.close()
-    except EnvironmentError:
+        with open(versionfile_abs, "r") as fobj:
+            for line in fobj:
+                if line.strip().startswith("git_refnames ="):
+                    mo = re.search(r'=\s*"(.*)"', line)
+                    if mo:
+                        keywords["refnames"] = mo.group(1)
+                if line.strip().startswith("git_full ="):
+                    mo = re.search(r'=\s*"(.*)"', line)
+                    if mo:
+                        keywords["full"] = mo.group(1)
+                if line.strip().startswith("git_date ="):
+                    mo = re.search(r'=\s*"(.*)"', line)
+                    if mo:
+                        keywords["date"] = mo.group(1)
+    except OSError:
         pass
     return keywords
 
@@ -973,10 +1092,14 @@ def git_get_keywords(versionfile_abs):
 @register_vcs_handler("git", "keywords")
 def git_versions_from_keywords(keywords, tag_prefix, verbose):
     """Get version information from git keywords."""
-    if not keywords:
-        raise NotThisMethod("no keywords at all, weird")
+    if "refnames" not in keywords:
+        raise NotThisMethod("Short version file found")
     date = keywords.get("date")
     if date is not None:
+        # Use only the last line.  Previous lines may contain GPG signature
+        # information.
+        date = date.splitlines()[-1]
+
         # git-2.2.0 added "%cI", which expands to an ISO-8601 -compliant
         # datestamp. However we prefer "%ci" (which expands to an "ISO-8601
         # -like" string, which we must then edit to make compliant), because
@@ -989,11 +1112,11 @@ def git_versions_from_keywords(keywords, tag_prefix, verbose):
         if verbose:
             print("keywords are unexpanded, not using")
         raise NotThisMethod("unexpanded keywords, not a git-archive tarball")
-    refs = set([r.strip() for r in refnames.strip("()").split(",")])
+    refs = {r.strip() for r in refnames.strip("()").split(",")}
     # starting in git-1.8.3, tags are listed as "tag: foo-1.0" instead of
     # just "foo-1.0". If we see a "tag: " prefix, prefer those.
     TAG = "tag: "
-    tags = set([r[len(TAG):] for r in refs if r.startswith(TAG)])
+    tags = {r[len(TAG):] for r in refs if r.startswith(TAG)}
     if not tags:
         # Either we're using git < 1.8.3, or there really are no tags. We use
         # a heuristic: assume all version tags have a digit. The old git %d
@@ -1002,7 +1125,7 @@ def git_versions_from_keywords(keywords, tag_prefix, verbose):
         # between branches and tags. By ignoring refnames without digits, we
         # filter out many common branch names like "release" and
         # "stabilization", as well as "HEAD" and "master".
-        tags = set([r for r in refs if re.search(r'\d', r)])
+        tags = {r for r in refs if re.search(r'\d', r)}
         if verbose:
             print("discarding '%s', no digits" % ",".join(refs - tags))
     if verbose:
@@ -1011,6 +1134,11 @@ def git_versions_from_keywords(keywords, tag_prefix, verbose):
         # sorting will prefer e.g. "2.0" over "2.0rc1"
         if ref.startswith(tag_prefix):
             r = ref[len(tag_prefix):]
+            # Filter out refs that exactly match prefix or that don't start
+            # with a number once the prefix is stripped (mostly a concern
+            # when prefix is '')
+            if not re.match(r'\d', r):
+                continue
             if verbose:
                 print("picking %s" % r)
             return {"version": r,
@@ -1026,7 +1154,7 @@ def git_versions_from_keywords(keywords, tag_prefix, verbose):
 
 
 @register_vcs_handler("git", "pieces_from_vcs")
-def git_pieces_from_vcs(tag_prefix, root, verbose, run_command=run_command):
+def git_pieces_from_vcs(tag_prefix, root, verbose, runner=run_command):
     """Get version from 'git describe' in the root of the source tree.
 
     This only gets called if the git-archive 'subst' keywords were *not*
@@ -1034,11 +1162,13 @@ def git_pieces_from_vcs(tag_prefix, root, verbose, run_command=run_command):
     version string, meaning we're inside a checked out source tree.
     """
     GITS = ["git"]
+    TAG_PREFIX_REGEX = "*"
     if sys.platform == "win32":
         GITS = ["git.cmd", "git.exe"]
+        TAG_PREFIX_REGEX = r"\*"
 
-    out, rc = run_command(GITS, ["rev-parse", "--git-dir"], cwd=root,
-                          hide_stderr=True)
+    _, rc = runner(GITS, ["rev-parse", "--git-dir"], cwd=root,
+                   hide_stderr=True)
     if rc != 0:
         if verbose:
             print("Directory %s not under git control" % root)
@@ -1046,15 +1176,16 @@ def git_pieces_from_vcs(tag_prefix, root, verbose, run_command=run_command):
 
     # if there is a tag matching tag_prefix, this yields TAG-NUM-gHEX[-dirty]
     # if there isn't one, this yields HEX[-dirty] (no NUM)
-    describe_out, rc = run_command(GITS, ["describe", "--tags", "--dirty",
-                                          "--always", "--long",
-                                          "--match", "%s*" % tag_prefix],
-                                   cwd=root)
+    describe_out, rc = runner(GITS, ["describe", "--tags", "--dirty",
+                                     "--always", "--long",
+                                     "--match",
+                                     "%s%s" % (tag_prefix, TAG_PREFIX_REGEX)],
+                              cwd=root)
     # --long was added in git-1.5.5
     if describe_out is None:
         raise NotThisMethod("'git describe' failed")
     describe_out = describe_out.strip()
-    full_out, rc = run_command(GITS, ["rev-parse", "HEAD"], cwd=root)
+    full_out, rc = runner(GITS, ["rev-parse", "HEAD"], cwd=root)
     if full_out is None:
         raise NotThisMethod("'git rev-parse' failed")
     full_out = full_out.strip()
@@ -1064,6 +1195,39 @@ def git_pieces_from_vcs(tag_prefix, root, verbose, run_command=run_command):
     pieces["short"] = full_out[:7]  # maybe improved later
     pieces["error"] = None
 
+    branch_name, rc = runner(GITS, ["rev-parse", "--abbrev-ref", "HEAD"],
+                             cwd=root)
+    # --abbrev-ref was added in git-1.6.3
+    if rc != 0 or branch_name is None:
+        raise NotThisMethod("'git rev-parse --abbrev-ref' returned error")
+    branch_name = branch_name.strip()
+
+    if branch_name == "HEAD":
+        # If we aren't exactly on a branch, pick a branch which represents
+        # the current commit. If all else fails, we are on a branchless
+        # commit.
+        branches, rc = runner(GITS, ["branch", "--contains"], cwd=root)
+        # --contains was added in git-1.5.4
+        if rc != 0 or branches is None:
+            raise NotThisMethod("'git branch --contains' returned error")
+        branches = branches.split("\n")
+
+        # Remove the first line if we're running detached
+        if "(" in branches[0]:
+            branches.pop(0)
+
+        # Strip off the leading "* " from the list of branches.
+        branches = [branch[2:] for branch in branches]
+        if "master" in branches:
+            branch_name = "master"
+        elif not branches:
+            branch_name = None
+        else:
+            # Pick the first branch that is returned. Good or bad.
+            branch_name = branches[0]
+
+    pieces["branch"] = branch_name
+
     # parse describe_out. It will be like TAG-NUM-gHEX[-dirty] or HEX[-dirty]
     # TAG might have hyphens.
     git_describe = describe_out
@@ -1080,7 +1244,7 @@ def git_pieces_from_vcs(tag_prefix, root, verbose, run_command=run_command):
         # TAG-NUM-gHEX
         mo = re.search(r'^(.+)-(\d+)-g([0-9a-f]+)$', git_describe)
         if not mo:
-            # unparseable. Maybe git-describe is misbehaving?
+            # unparsable. Maybe git-describe is misbehaving?
             pieces["error"] = ("unable to parse git-describe output: '%s'"
                                % describe_out)
             return pieces
@@ -1105,13 +1269,14 @@ def git_pieces_from_vcs(tag_prefix, root, verbose, run_command=run_command):
     else:
         # HEX: no tags
         pieces["closest-tag"] = None
-        count_out, rc = run_command(GITS, ["rev-list", "HEAD", "--count"],
-                                    cwd=root)
+        count_out, rc = runner(GITS, ["rev-list", "HEAD", "--count"], cwd=root)
         pieces["distance"] = int(count_out)  # total number of commits
 
     # commit date: see ISO-8601 comment in git_versions_from_keywords()
-    date = run_command(GITS, ["show", "-s", "--format=%ci", "HEAD"],
-                       cwd=root)[0].strip()
+    date = runner(GITS, ["show", "-s", "--format=%ci", "HEAD"], cwd=root)[0].strip()
+    # Use only the last line.  Previous lines may contain GPG signature
+    # information.
+    date = date.splitlines()[-1]
     pieces["date"] = date.strip().replace(" ", "T", 1).replace(" ", "", 1)
 
     return pieces
@@ -1130,27 +1295,26 @@ def do_vcs_install(manifest_in, versionfile_source, ipy):
     if ipy:
         files.append(ipy)
     try:
-        me = __file__
-        if me.endswith(".pyc") or me.endswith(".pyo"):
-            me = os.path.splitext(me)[0] + ".py"
-        versioneer_file = os.path.relpath(me)
+        my_path = __file__
+        if my_path.endswith(".pyc") or my_path.endswith(".pyo"):
+            my_path = os.path.splitext(my_path)[0] + ".py"
+        versioneer_file = os.path.relpath(my_path)
     except NameError:
         versioneer_file = "versioneer.py"
     files.append(versioneer_file)
     present = False
     try:
-        f = open(".gitattributes", "r")
-        for line in f.readlines():
-            if line.strip().startswith(versionfile_source):
-                if "export-subst" in line.strip().split()[1:]:
-                    present = True
-        f.close()
-    except EnvironmentError:
+        with open(".gitattributes", "r") as fobj:
+            for line in fobj:
+                if line.strip().startswith(versionfile_source):
+                    if "export-subst" in line.strip().split()[1:]:
+                        present = True
+                        break
+    except OSError:
         pass
     if not present:
-        f = open(".gitattributes", "a+")
-        f.write("%s export-subst\n" % versionfile_source)
-        f.close()
+        with open(".gitattributes", "a+") as fobj:
+            fobj.write(f"{versionfile_source} export-subst\n")
         files.append(".gitattributes")
     run_command(GITS, ["add", "--"] + files)
 
@@ -1164,15 +1328,14 @@ def versions_from_parentdir(parentdir_prefix, root, verbose):
     """
     rootdirs = []
 
-    for i in range(3):
+    for _ in range(3):
         dirname = os.path.basename(root)
         if dirname.startswith(parentdir_prefix):
             return {"version": dirname[len(parentdir_prefix):],
                     "full-revisionid": None,
                     "dirty": False, "error": None, "date": None}
-        else:
-            rootdirs.append(root)
-            root = os.path.dirname(root)  # up a level
+        rootdirs.append(root)
+        root = os.path.dirname(root)  # up a level
 
     if verbose:
         print("Tried directories %s but none started with prefix %s" %
@@ -1181,7 +1344,7 @@ def versions_from_parentdir(parentdir_prefix, root, verbose):
 
 
 SHORT_VERSION_PY = """
-# This file was generated by 'versioneer.py' (0.18) from
+# This file was generated by 'versioneer.py' (0.21) from
 # revision-control system data, or from the parent directory name of an
 # unpacked source archive. Distribution tarballs contain a pre-generated copy
 # of this file.
@@ -1203,7 +1366,7 @@ def versions_from_file(filename):
     try:
         with open(filename) as f:
             contents = f.read()
-    except EnvironmentError:
+    except OSError:
         raise NotThisMethod("unable to read _version.py")
     mo = re.search(r"version_json = '''\n(.*)'''  # END VERSION_JSON",
                    contents, re.M | re.S)
@@ -1258,19 +1421,67 @@ def render_pep440(pieces):
     return rendered
 
 
-def render_pep440_pre(pieces):
-    """TAG[.post.devDISTANCE] -- No -dirty.
+def render_pep440_branch(pieces):
+    """TAG[[.dev0]+DISTANCE.gHEX[.dirty]] .
+
+    The ".dev0" means not master branch. Note that .dev0 sorts backwards
+    (a feature branch will appear "older" than the master branch).
 
     Exceptions:
-    1: no tags. 0.post.devDISTANCE
+    1: no tags. 0[.dev0]+untagged.DISTANCE.gHEX[.dirty]
     """
     if pieces["closest-tag"]:
         rendered = pieces["closest-tag"]
+        if pieces["distance"] or pieces["dirty"]:
+            if pieces["branch"] != "master":
+                rendered += ".dev0"
+            rendered += plus_or_dot(pieces)
+            rendered += "%d.g%s" % (pieces["distance"], pieces["short"])
+            if pieces["dirty"]:
+                rendered += ".dirty"
+    else:
+        # exception #1
+        rendered = "0"
+        if pieces["branch"] != "master":
+            rendered += ".dev0"
+        rendered += "+untagged.%d.g%s" % (pieces["distance"],
+                                          pieces["short"])
+        if pieces["dirty"]:
+            rendered += ".dirty"
+    return rendered
+
+
+def pep440_split_post(ver):
+    """Split pep440 version string at the post-release segment.
+
+    Returns the release segments before the post-release and the
+    post-release version number (or -1 if no post-release segment is present).
+    """
+    vc = str.split(ver, ".post")
+    return vc[0], int(vc[1] or 0) if len(vc) == 2 else None
+
+
+def render_pep440_pre(pieces):
+    """TAG[.postN.devDISTANCE] -- No -dirty.
+
+    Exceptions:
+    1: no tags. 0.post0.devDISTANCE
+    """
+    if pieces["closest-tag"]:
         if pieces["distance"]:
-            rendered += ".post.dev%d" % pieces["distance"]
+            # update the post release segment
+            tag_version, post_version = pep440_split_post(pieces["closest-tag"])
+            rendered = tag_version
+            if post_version is not None:
+                rendered += ".post%d.dev%d" % (post_version+1, pieces["distance"])
+            else:
+                rendered += ".post0.dev%d" % (pieces["distance"])
+        else:
+            # no commits, use the tag as the version
+            rendered = pieces["closest-tag"]
     else:
         # exception #1
-        rendered = "0.post.dev%d" % pieces["distance"]
+        rendered = "0.post0.dev%d" % pieces["distance"]
     return rendered
 
 
@@ -1301,12 +1512,41 @@ def render_pep440_post(pieces):
     return rendered
 
 
+def render_pep440_post_branch(pieces):
+    """TAG[.postDISTANCE[.dev0]+gHEX[.dirty]] .
+
+    The ".dev0" means not master branch.
+
+    Exceptions:
+    1: no tags. 0.postDISTANCE[.dev0]+gHEX[.dirty]
+    """
+    if pieces["closest-tag"]:
+        rendered = pieces["closest-tag"]
+        if pieces["distance"] or pieces["dirty"]:
+            rendered += ".post%d" % pieces["distance"]
+            if pieces["branch"] != "master":
+                rendered += ".dev0"
+            rendered += plus_or_dot(pieces)
+            rendered += "g%s" % pieces["short"]
+            if pieces["dirty"]:
+                rendered += ".dirty"
+    else:
+        # exception #1
+        rendered = "0.post%d" % pieces["distance"]
+        if pieces["branch"] != "master":
+            rendered += ".dev0"
+        rendered += "+g%s" % pieces["short"]
+        if pieces["dirty"]:
+            rendered += ".dirty"
+    return rendered
+
+
 def render_pep440_old(pieces):
     """TAG[.postDISTANCE[.dev0]] .
 
     The ".dev0" means dirty.
 
-    Eexceptions:
+    Exceptions:
     1: no tags. 0.postDISTANCE[.dev0]
     """
     if pieces["closest-tag"]:
@@ -1377,10 +1617,14 @@ def render(pieces, style):
 
     if style == "pep440":
         rendered = render_pep440(pieces)
+    elif style == "pep440-branch":
+        rendered = render_pep440_branch(pieces)
     elif style == "pep440-pre":
         rendered = render_pep440_pre(pieces)
     elif style == "pep440-post":
         rendered = render_pep440_post(pieces)
+    elif style == "pep440-post-branch":
+        rendered = render_pep440_post_branch(pieces)
     elif style == "pep440-old":
         rendered = render_pep440_old(pieces)
     elif style == "git-describe":
@@ -1480,8 +1724,12 @@ def get_version():
     return get_versions()["version"]
 
 
-def get_cmdclass():
-    """Get the custom setuptools/distutils subclasses used by Versioneer."""
+def get_cmdclass(cmdclass=None):
+    """Get the custom setuptools/distutils subclasses used by Versioneer.
+
+    If the package uses a different cmdclass (e.g. one from numpy), it
+    should be provide as an argument.
+    """
     if "versioneer" in sys.modules:
         del sys.modules["versioneer"]
         # this fixes the "python setup.py develop" case (also 'install' and
@@ -1495,9 +1743,9 @@ def get_cmdclass():
         # parent is protected against the child's "import versioneer". By
         # removing ourselves from sys.modules here, before the child build
         # happens, we protect the child from the parent's versioneer too.
-        # Also see https://github.com/warner/python-versioneer/issues/52
+        # Also see https://github.com/python-versioneer/python-versioneer/issues/52
 
-    cmds = {}
+    cmds = {} if cmdclass is None else cmdclass.copy()
 
     # we add "version" to both distutils and setuptools
     from distutils.core import Command
@@ -1539,7 +1787,9 @@ def run(self):
     #  setup.py egg_info -> ?
 
     # we override different "build_py" commands for both environments
-    if "setuptools" in sys.modules:
+    if 'build_py' in cmds:
+        _build_py = cmds['build_py']
+    elif "setuptools" in sys.modules:
         from setuptools.command.build_py import build_py as _build_py
     else:
         from distutils.command.build_py import build_py as _build_py
@@ -1559,6 +1809,33 @@ def run(self):
                 write_to_version_file(target_versionfile, versions)
     cmds["build_py"] = cmd_build_py
 
+    if 'build_ext' in cmds:
+        _build_ext = cmds['build_ext']
+    elif "setuptools" in sys.modules:
+        from setuptools.command.build_ext import build_ext as _build_ext
+    else:
+        from distutils.command.build_ext import build_ext as _build_ext
+
+    class cmd_build_ext(_build_ext):
+        def run(self):
+            root = get_root()
+            cfg = get_config_from_root(root)
+            versions = get_versions()
+            _build_ext.run(self)
+            if self.inplace:
+                # build_ext --inplace will only build extensions in
+                # build/lib<..> dir with no _version.py to write to.
+                # As in place builds will already have a _version.py
+                # in the module dir, we do not need to write one.
+                return
+            # now locate _version.py in the new build/ directory and replace
+            # it with an updated value
+            target_versionfile = os.path.join(self.build_lib,
+                                              cfg.versionfile_build)
+            print("UPDATING %s" % target_versionfile)
+            write_to_version_file(target_versionfile, versions)
+    cmds["build_ext"] = cmd_build_ext
+
     if "cx_Freeze" in sys.modules:  # cx_freeze enabled?
         from cx_Freeze.dist import build_exe as _build_exe
         # nczeczulin reports that py2exe won't like the pep440-style string
@@ -1592,10 +1869,7 @@ def run(self):
         del cmds["build_py"]
 
     if 'py2exe' in sys.modules:  # py2exe enabled?
-        try:
-            from py2exe.distutils_buildexe import py2exe as _py2exe  # py3
-        except ImportError:
-            from py2exe.build_exe import py2exe as _py2exe  # py2
+        from py2exe.distutils_buildexe import py2exe as _py2exe
 
         class cmd_py2exe(_py2exe):
             def run(self):
@@ -1620,7 +1894,9 @@ def run(self):
         cmds["py2exe"] = cmd_py2exe
 
     # we override different "sdist" commands for both environments
-    if "setuptools" in sys.modules:
+    if 'sdist' in cmds:
+        _sdist = cmds['sdist']
+    elif "setuptools" in sys.modules:
         from setuptools.command.sdist import sdist as _sdist
     else:
         from distutils.command.sdist import sdist as _sdist
@@ -1687,21 +1963,26 @@ def make_release_tree(self, base_dir, files):
 
 """
 
-INIT_PY_SNIPPET = """
+OLD_SNIPPET = """
 from ._version import get_versions
 __version__ = get_versions()['version']
 del get_versions
 """
 
+INIT_PY_SNIPPET = """
+from . import {0}
+__version__ = {0}.get_versions()['version']
+"""
+
 
 def do_setup():
-    """Main VCS-independent setup function for installing Versioneer."""
+    """Do main VCS-independent setup function for installing Versioneer."""
     root = get_root()
     try:
         cfg = get_config_from_root(root)
-    except (EnvironmentError, configparser.NoSectionError,
+    except (OSError, configparser.NoSectionError,
             configparser.NoOptionError) as e:
-        if isinstance(e, (EnvironmentError, configparser.NoSectionError)):
+        if isinstance(e, (OSError, configparser.NoSectionError)):
             print("Adding sample versioneer config to setup.cfg",
                   file=sys.stderr)
             with open(os.path.join(root, "setup.cfg"), "a") as f:
@@ -1725,12 +2006,18 @@ def do_setup():
         try:
             with open(ipy, "r") as f:
                 old = f.read()
-        except EnvironmentError:
+        except OSError:
             old = ""
-        if INIT_PY_SNIPPET not in old:
+        module = os.path.splitext(os.path.basename(cfg.versionfile_source))[0]
+        snippet = INIT_PY_SNIPPET.format(module)
+        if OLD_SNIPPET in old:
+            print(" replacing boilerplate in %s" % ipy)
+            with open(ipy, "w") as f:
+                f.write(old.replace(OLD_SNIPPET, snippet))
+        elif snippet not in old:
             print(" appending to %s" % ipy)
             with open(ipy, "a") as f:
-                f.write(INIT_PY_SNIPPET)
+                f.write(snippet)
         else:
             print(" %s unmodified" % ipy)
     else:
@@ -1749,7 +2036,7 @@ def do_setup():
                 if line.startswith("include "):
                     for include in line.split()[1:]:
                         simple_includes.add(include)
-    except EnvironmentError:
+    except OSError:
         pass
     # That doesn't cover everything MANIFEST.in can do
     # (http://docs.python.org/2/distutils/sourcedist.html#commands), so


Test patch:
diff --git a/conftest.py b/conftest.py
index 5a17f7a..eef86c1 100644
--- a/conftest.py
+++ b/conftest.py
@@ -1,5 +1,17 @@
+import pytest
+from sphinx.testing.path import path
+
+
 try:
     import pytest_doctestplus.plugin
     pytest_doctestplus
 except ImportError:
     raise ImportError("Install pytest-doctestplus to run the tests")
+
+
+pytest_plugins = 'sphinx.testing.fixtures'
+
+
+@pytest.fixture(scope='session')
+def rootdir():
+    return path(__file__).parent.abspath() / 'sphinx_math_dollar' / 'tests'
diff --git a/sphinx_math_dollar/tests/test-build/Makefile b/sphinx_math_dollar/tests/test-root/Makefile
similarity index 100%
rename from sphinx_math_dollar/tests/test-build/Makefile
rename to sphinx_math_dollar/tests/test-root/Makefile
diff --git a/sphinx_math_dollar/tests/test-build/conf.py b/sphinx_math_dollar/tests/test-root/conf.py
similarity index 100%
rename from sphinx_math_dollar/tests/test-build/conf.py
rename to sphinx_math_dollar/tests/test-root/conf.py
diff --git a/sphinx_math_dollar/tests/test-build/index.rst b/sphinx_math_dollar/tests/test-root/index.rst
similarity index 100%
rename from sphinx_math_dollar/tests/test-build/index.rst
rename to sphinx_math_dollar/tests/test-root/index.rst
diff --git a/sphinx_math_dollar/tests/test-build/make.bat b/sphinx_math_dollar/tests/test-root/make.bat
similarity index 100%
rename from sphinx_math_dollar/tests/test-build/make.bat
rename to sphinx_math_dollar/tests/test-root/make.bat
diff --git a/sphinx_math_dollar/tests/test_extension.py b/sphinx_math_dollar/tests/test_extension.py
index fa8cf72..655d6f9 100644
--- a/sphinx_math_dollar/tests/test_extension.py
+++ b/sphinx_math_dollar/tests/test_extension.py
@@ -1,10 +1,12 @@
-import os
+import pytest
 
-from sphinx_testing import with_app
 
-@with_app(buildername='html', srcdir=os.path.join(os.path.dirname(__file__), 'test-build'),
-          copy_srcdir_to_tmpdir=True)
-def _test_sphinx_build(app, status, warning):
+def test(app):
+    app.build()
+
+
+@pytest.mark.sphinx(buildername='html')
+def test_sphinx_build(app, status, warning):
     app.build()
     html = (app.outdir/'index.html').read_text()
 
@@ -23,6 +25,3 @@ def _test_sphinx_build(app, status, warning):
 
     assert not status.read()
     assert not warning.read()
-
-def test_sphinx_build():
-    _test_sphinx_build()