text: """pytest configuration
  
  Extends output capture as needed by pybind11: ignore constructors, optional unordered lines.
  Adds docstring and exceptions message sanitizers: ignore Python 2 vs 3 differences.
  """
  
  import pytest
  import textwrap
  import difflib
  import re
  import sys
  import contextlib
  import platform
  import gc
  
  _unicode_marker = re.compile(r'u(\'[^\']*\')')
  _long_marker = re.compile(r'([0-9])L')
  _hexadecimal = re.compile(r'0x[0-9a-fA-F]+')
  
  # test_async.py requires support for async and await
  collect_ignore = []
  if sys.version_info[:2] < (3, 5):
      collect_ignore.append("test_async.py")
  
  
  def _strip_and_dedent(s):
      """For triple-quote strings"""
      return textwrap.dedent(s.lstrip('\n').rstrip())
  
  
  def _split_and_sort(s):
      """For output which does not require specific line order"""
      return sorted(_strip_and_dedent(s).splitlines())
  
  
  def _make_explanation(a, b):
      """Explanation for a failed assert -- the a and b arguments are List[str]"""
      return ["--- actual / +++ expected"] + [line.strip('\n') for line in difflib.ndiff(a, b)]
  
  
  class Output(object):
      """Basic output post-processing and comparison"""
      def __init__(self, string):
          self.string = string
          self.explanation = []
  
      def __str__(self):
          return self.string
  
      def __eq__(self, other):
          # Ignore constructor/destructor output which is prefixed with "###"
          a = [line for line in self.string.strip().splitlines() if not line.startswith("###")]
          b = _strip_and_dedent(other).splitlines()
          if a == b:
              return True
          else:
              self.explanation = _make_explanation(a, b)
              return False
  
  
  class Unordered(Output):
      """Custom comparison for output without strict line ordering"""
      def __eq__(self, other):
          a = _split_and_sort(self.string)
          b = _split_and_sort(other)
          if a == b:
              return True
          else:
              self.explanation = _make_explanation(a, b)
              return False
  
  
  class Capture(object):
      def __init__(self, capfd):
          self.capfd = capfd
          self.out = ""
          self.err = ""
  
      def __enter__(self):
          self.capfd.readouterr()
          return self
  
      def __exit__(self, *args):
          self.out, self.err = self.capfd.readouterr()
  
      def __eq__(self, other):
          a = Output(self.out)
          b = other
          if a == b:
              return True
          else:
              self.explanation = a.explanation
              return False
  
      def __str__(self):
          return self.out
  
      def __contains__(self, item):
          return item in self.out
  
      @property
      def unordered(self):
          return Unordered(self.out)
  
      @property
      def stderr(self):
          return Output(self.err)
  
  
  @pytest.fixture
  def capture(capsys):
      """Extended `capsys` with context manager and custom equality operators"""
      return Capture(capsys)
  
  
  class SanitizedString(object):
      def __init__(self, sanitizer):
          self.sanitizer = sanitizer
          self.string = ""
          self.explanation = []
  
      def __call__(self, thing):
          self.string = self.sanitizer(thing)
          return self
  
      def __eq__(self, other):
          a = self.string
          b = _strip_and_dedent(other)
          if a == b:
              return True
          else:
              self.explanation = _make_explanation(a.splitlines(), b.splitlines())
              return False
  
  
  def _sanitize_general(s):
      s = s.strip()
      s = s.replace("pybind11_tests.", "m.")
      s = s.replace("unicode", "str")
      s = _long_marker.sub(r"\1", s)
      s = _unicode_marker.sub(r"\1", s)
      return s
  
  
  def _sanitize_docstring(thing):
      s = thing.__doc__
      s = _sanitize_general(s)
      return s
  
  
  @pytest.fixture
  def doc():
      """Sanitize docstrings and add custom failure explanation"""
      return SanitizedString(_sanitize_docstring)
  
  
  def _sanitize_message(thing):
      s = str(thing)
      s = _sanitize_general(s)
      s = _hexadecimal.sub("0", s)
      return s
  
  
  @pytest.fixture
  def msg():
      """Sanitize messages and add custom failure explanation"""
      return SanitizedString(_sanitize_message)
  
  
  # noinspection PyUnusedLocal
  def pytest_assertrepr_compare(op, left, right):
      """Hook to insert custom failure explanation"""
      if hasattr(left, 'explanation'):
          return left.explanation
  
  
  @contextlib.contextmanager
  def suppress(exception):
      """Suppress the desired exception"""
      try:
          yield
      except exception:
          pass
  
  
  def gc_collect():
      ''' Run the garbage collector twice (needed when running
      reference counting tests with PyPy) '''
      gc.collect()
      gc.collect()
  
  
  def pytest_configure():
      """Add import suppression and test requirements to `pytest` namespace"""
      try:
          import numpy as np
      except ImportError:
          np = None
      try:
          import scipy
      except ImportError:
          scipy = None
      try:
          from pybind11_tests.eigen import have_eigen
      except ImportError:
          have_eigen = False
      pypy = platform.python_implementation() == "PyPy"
  
      skipif = pytest.mark.skipif
      pytest.suppress = suppress
      pytest.requires_numpy = skipif(not np, reason="numpy is not installed")
      pytest.requires_scipy = skipif(not np, reason="scipy is not installed")
      pytest.requires_eigen_and_numpy = skipif(not have_eigen or not np,
                                               reason="eigen and/or numpy are not installed")
      pytest.requires_eigen_and_scipy = skipif(
          not have_eigen or not scipy, reason="eigen and/or scipy are not installed")
      pytest.unsupported_on_pypy = skipif(pypy, reason="unsupported on PyPy")
      pytest.unsupported_on_py2 = skipif(sys.version_info.major < 3,
                                         reason="unsupported on Python 2.x")
      pytest.gc_collect = gc_collect
  
  
  def _test_import_pybind11():
      """Early diagnostic for test module initialization errors
  
      When there is an error during initialization, the first import will report the
      real error while all subsequent imports will report nonsense. This import test
      is done early (in the pytest configuration file, before any tests) in order to
      avoid the noise of having all tests fail with identical error messages.
  
      Any possible exception is caught here and reported manually *without* the stack
      trace. This further reduces noise since the trace would only show pytest internals
      which are not useful for debugging pybind11 module issues.
      """
      # noinspection PyBroadException
      try:
          import pybind11_tests  # noqa: F401 imported but unused
      except Exception as e:
          print("Failed to import pybind11_tests from pytest:")
          print("  {}: {}".format(type(e).__name__, e))
          sys.exit(1)
  
  
  _test_import_pybind11()
  