text: """Utilities for processing .test files containing test case descriptions."""
  
  import os.path
  import os
  import tempfile
  import posixpath
  import re
  import shutil
  from abc import abstractmethod
  import sys
  
  import pytest  # type: ignore  # no pytest in typeshed
  from typing import List, Tuple, Set, Optional, Iterator, Any, Dict, NamedTuple, Union
  
  from mypy.test.config import test_data_prefix, test_temp_dir, PREFIX
  
  root_dir = os.path.normpath(PREFIX)
  
  # File modify/create operation: copy module contents from source_path.
  UpdateFile = NamedTuple(
      "UpdateFile", [("module", str), ("source_path", str), ("target_path", str)]
  )
  
  # File delete operation: delete module file.
  DeleteFile = NamedTuple("DeleteFile", [("module", str), ("path", str)])
  
  FileOperation = Union[UpdateFile, DeleteFile]
  
  
  def parse_test_case(case: "DataDrivenTestCase") -> None:
      """Parse and prepare a single case from suite with test case descriptions.
  
      This method is part of the setup phase, just before the test case is run.
      """
      test_items = parse_test_data(case.data, case.name)
      base_path = case.suite.base_path
      if case.suite.native_sep:
          join = os.path.join
      else:
          join = posixpath.join
  
      out_section_missing = case.suite.required_out_section
      normalize_output = True
  
      files = []  # type: List[Tuple[str, str]] # path and contents
      output_files = (
          []
      )  # type: List[Tuple[str, str]] # path and contents for output files
      output = []  # type: List[str]  # Regular output errors
      output2 = {}  # type: Dict[int, List[str]]  # Output errors for incremental, runs 2+
      deleted_paths = {}  # type: Dict[int, Set[str]]  # from run number of paths
      stale_modules = {}  # type: Dict[int, Set[str]]  # from run number to module names
      rechecked_modules = {}  # type: Dict[ int, Set[str]]  # from run number module names
      triggered = []  # type: List[str]  # Active triggers (one line per incremental step)
      targets = (
          {}
      )  # type: Dict[int, List[str]]  # Fine-grained targets (per fine-grained update)
  
      # Process the parsed items. Each item has a header of form [id args],
      # optionally followed by lines of text.
      item = first_item = test_items[0]
      for item in test_items[1:]:
          if item.id == "file" or item.id == "outfile":
              # Record an extra file needed for the test case.
              assert item.arg is not None
              contents = expand_variables("\n".join(item.data))
              file_entry = (join(base_path, item.arg), contents)
              if item.id == "file":
                  files.append(file_entry)
              else:
                  output_files.append(file_entry)
          elif item.id in ("builtins", "builtins_py2"):
              # Use an alternative stub file for the builtins module.
              assert item.arg is not None
              mpath = join(os.path.dirname(case.file), item.arg)
              fnam = "builtins.pyi" if item.id == "builtins" else "__builtin__.pyi"
              with open(mpath, encoding="utf8") as f:
                  files.append((join(base_path, fnam), f.read()))
          elif item.id == "typing":
              # Use an alternative stub file for the typing module.
              assert item.arg is not None
              src_path = join(os.path.dirname(case.file), item.arg)
              with open(src_path, encoding="utf8") as f:
                  files.append((join(base_path, "typing.pyi"), f.read()))
          elif re.match(r"stale[0-9]*$", item.id):
              passnum = 1 if item.id == "stale" else int(item.id[len("stale") :])
              assert passnum > 0
              modules = (
                  set() if item.arg is None else {t.strip() for t in item.arg.split(",")}
              )
              stale_modules[passnum] = modules
          elif re.match(r"rechecked[0-9]*$", item.id):
              passnum = 1 if item.id == "rechecked" else int(item.id[len("rechecked") :])
              assert passnum > 0
              modules = (
                  set() if item.arg is None else {t.strip() for t in item.arg.split(",")}
              )
              rechecked_modules[passnum] = modules
          elif re.match(r"targets[0-9]*$", item.id):
              passnum = 1 if item.id == "targets" else int(item.id[len("targets") :])
              assert passnum > 0
              reprocessed = (
                  [] if item.arg is None else [t.strip() for t in item.arg.split(",")]
              )
              targets[passnum] = reprocessed
          elif item.id == "delete":
              # File to delete during a multi-step test case
              assert item.arg is not None
              m = re.match(r"(.*)\.([0-9]+)$", item.arg)
              assert m, "Invalid delete section: {}".format(item.arg)
              num = int(m.group(2))
              assert num >= 2, "Can't delete during step {}".format(num)
              full = join(base_path, m.group(1))
              deleted_paths.setdefault(num, set()).add(full)
          elif re.match(r"out[0-9]*$", item.id):
              if item.arg == "skip-path-normalization":
                  normalize_output = False
  
              tmp_output = [expand_variables(line) for line in item.data]
              if os.path.sep == "\\" and normalize_output:
                  tmp_output = [fix_win_path(line) for line in tmp_output]
              if item.id == "out" or item.id == "out1":
                  output = tmp_output
              else:
                  passnum = int(item.id[len("out") :])
                  assert passnum > 1
                  output2[passnum] = tmp_output
              out_section_missing = False
          elif item.id == "triggered" and item.arg is None:
              triggered = item.data
          else:
              raise ValueError(
                  "Invalid section header {} in {} at line {}".format(
                      item.id, case.file, item.line
                  )
              )
  
      if out_section_missing:
          raise ValueError(
              "{}, line {}: Required output section not found".format(
                  case.file, first_item.line
              )
          )
  
      for passnum in stale_modules.keys():
          if passnum not in rechecked_modules:
              # If the set of rechecked modules isn't specified, make it the same as the set
              # of modules with a stale public interface.
              rechecked_modules[passnum] = stale_modules[passnum]
          if (
              passnum in stale_modules
              and passnum in rechecked_modules
              and not stale_modules[passnum].issubset(rechecked_modules[passnum])
          ):
              raise ValueError(
                  (
                      "Stale modules after pass {} must be a subset of rechecked "
                      "modules ({}:{})"
                  ).format(passnum, case.file, first_item.line)
              )
  
      input = first_item.data
      expand_errors(input, output, "main")
      for file_path, contents in files:
          expand_errors(contents.split("\n"), output, file_path)
  
      case.input = input
      case.output = output
      case.output2 = output2
      case.lastline = item.line
      case.files = files
      case.output_files = output_files
      case.expected_stale_modules = stale_modules
      case.expected_rechecked_modules = rechecked_modules
      case.deleted_paths = deleted_paths
      case.triggered = triggered or []
      case.normalize_output = normalize_output
      case.expected_fine_grained_targets = targets
  
  
  class DataDrivenTestCase(pytest.Item):  # type: ignore  # inheriting from Any
      """Holds parsed data-driven test cases, and handles directory setup and teardown."""
  
      input = None  # type: List[str]
      output = None  # type: List[str]  # Output for the first pass
      output2 = (
          None
      )  # type: Dict[int, List[str]]  # Output for runs 2+, indexed by run number
  
      # full path of test suite
      file = ""
      line = 0
  
      # (file path, file content) tuples
      files = None  # type: List[Tuple[str, str]]
      expected_stale_modules = None  # type: Dict[int, Set[str]]
      expected_rechecked_modules = None  # type: Dict[int, Set[str]]
      expected_fine_grained_targets = None  # type: Dict[int, List[str]]
  
      # Whether or not we should normalize the output to standardize things like
      # forward vs backward slashes in file paths for Windows vs Linux.
      normalize_output = True
  
      # Extra attributes used by some tests.
      lastline = None  # type: int
      output_files = (
          None
      )  # type: List[Tuple[str, str]] # Path and contents for output files
      deleted_paths = None  # type: Dict[int, Set[str]]  # Mapping run number -> paths
      triggered = (
          None
      )  # type: List[str]  # Active triggers (one line per incremental step)
  
      def __init__(
          self,
          parent: "DataSuiteCollector",
          suite: "DataSuite",
          file: str,
          name: str,
          writescache: bool,
          only_when: str,
          platform: Optional[str],
          skip: bool,
          data: str,
          line: int,
      ) -> None:
          super().__init__(name, parent)
          self.suite = suite
          self.file = file
          self.writescache = writescache
          self.only_when = only_when
          if (platform == "windows" and sys.platform != "win32") or (
              platform == "posix" and sys.platform == "win32"
          ):
              skip = True
          self.skip = skip
          self.data = data
          self.line = line
          self.old_cwd = None  # type: Optional[str]
          self.tmpdir = None  # type: Optional[tempfile.TemporaryDirectory[str]]
  
      def runtest(self) -> None:
          if self.skip:
              pytest.skip()
          suite = self.parent.obj()
          suite.setup()
          try:
              suite.run_case(self)
          except Exception:
              # As a debugging aid, support copying the contents of the tmp directory somewhere
              save_dir = self.config.getoption(
                  "--save-failures-to", None
              )  # type: Optional[str]
              if save_dir:
                  assert self.tmpdir is not None
                  target_dir = os.path.join(save_dir, os.path.basename(self.tmpdir.name))
                  print("Copying data from test {} to {}".format(self.name, target_dir))
                  if not os.path.isabs(target_dir):
                      assert self.old_cwd
                      target_dir = os.path.join(self.old_cwd, target_dir)
                  shutil.copytree(self.tmpdir.name, target_dir)
              raise
  
      def setup(self) -> None:
          parse_test_case(case=self)
          self.old_cwd = os.getcwd()
          self.tmpdir = tempfile.TemporaryDirectory(prefix="mypy-test-")
          os.chdir(self.tmpdir.name)
          os.mkdir(test_temp_dir)
          for path, content in self.files:
              dir = os.path.dirname(path)
              os.makedirs(dir, exist_ok=True)
              with open(path, "w", encoding="utf8") as f:
                  f.write(content)
  
      def teardown(self) -> None:
          assert (
              self.old_cwd is not None and self.tmpdir is not None
          ), "test was not properly set up"
          os.chdir(self.old_cwd)
          try:
              self.tmpdir.cleanup()
          except OSError:
              pass
          self.old_cwd = None
          self.tmpdir = None
  
      def reportinfo(self) -> Tuple[str, int, str]:
          return self.file, self.line, self.name
  
      def repr_failure(self, excinfo: Any, style: Optional[Any] = None) -> str:
          if excinfo.errisinstance(SystemExit):
              # We assume that before doing exit() (which raises SystemExit) we've printed
              # enough context about what happened so that a stack trace is not useful.
              # In particular, uncaught exceptions during semantic analysis or type checking
              # call exit() and they already print out a stack trace.
              excrepr = excinfo.exconly()
          else:
              self.parent._prunetraceback(excinfo)
              excrepr = excinfo.getrepr(style="short")
  
          return "data: {}:{}:\n{}".format(self.file, self.line, excrepr)
  
      def find_steps(self) -> List[List[FileOperation]]:
          """Return a list of descriptions of file operations for each incremental step.
  
          The first list item corresponds to the first incremental step, the second for the
          second step, etc. Each operation can either be a file modification/creation (UpdateFile)
          or deletion (DeleteFile).
  
          Defaults to having two steps if there aern't any operations.
          """
          steps = {}  # type: Dict[int, List[FileOperation]]
          for path, _ in self.files:
              m = re.match(r".*\.([0-9]+)$", path)
              if m:
                  num = int(m.group(1))
                  assert num >= 2
                  target_path = re.sub(r"\.[0-9]+$", "", path)
                  module = module_from_path(target_path)
                  operation = UpdateFile(module, path, target_path)
                  steps.setdefault(num, []).append(operation)
          for num, paths in self.deleted_paths.items():
              assert num >= 2
              for path in paths:
                  module = module_from_path(path)
                  steps.setdefault(num, []).append(DeleteFile(module, path))
          max_step = max(steps) if steps else 2
          return [steps.get(num, []) for num in range(2, max_step + 1)]
  
  
  def module_from_path(path: str) -> str:
      path = re.sub(r"\.pyi?$", "", path)
      # We can have a mix of Unix-style and Windows-style separators.
      parts = re.split(r"[/\\]", path)
      assert parts[0] == test_temp_dir
      del parts[0]
      module = ".".join(parts)
      module = re.sub(r"\.__init__$", "", module)
      return module
  
  
  class TestItem:
      """Parsed test caseitem.
  
      An item is of the form
        [id arg]
        .. data ..
      """
  
      id = ""
      arg = ""  # type: Optional[str]
  
      # Text data, array of 8-bit strings
      data = None  # type: List[str]
  
      file = ""
      line = 0  # Line number in file
  
      def __init__(self, id: str, arg: Optional[str], data: List[str], line: int) -> None:
          self.id = id
          self.arg = arg
          self.data = data
          self.line = line
  
  
  def parse_test_data(raw_data: str, name: str) -> List[TestItem]:
      """Parse a list of lines that represent a sequence of test items."""
  
      lines = ["", "[case " + name + "]"] + raw_data.split("\n")
      ret = []  # type: List[TestItem]
      data = []  # type: List[str]
  
      id = None  # type: Optional[str]
      arg = None  # type: Optional[str]
  
      i = 0
      i0 = 0
      while i < len(lines):
          s = lines[i].strip()
  
          if lines[i].startswith("[") and s.endswith("]"):
              if id:
                  data = collapse_line_continuation(data)
                  data = strip_list(data)
                  ret.append(TestItem(id, arg, strip_list(data), i0 + 1))
  
              i0 = i
              id = s[1:-1]
              arg = None
              if " " in id:
                  arg = id[id.index(" ") + 1 :]
                  id = id[: id.index(" ")]
              data = []
          elif lines[i].startswith("\\["):
              data.append(lines[i][1:])
          elif not lines[i].startswith("--"):
              data.append(lines[i])
          elif lines[i].startswith("----"):
              data.append(lines[i][2:])
          i += 1
  
      # Process the last item.
      if id:
          data = collapse_line_continuation(data)
          data = strip_list(data)
          ret.append(TestItem(id, arg, data, i0 + 1))
  
      return ret
  
  
  def strip_list(l: List[str]) -> List[str]:
      """Return a stripped copy of l.
  
      Strip whitespace at the end of all lines, and strip all empty
      lines from the end of the array.
      """
  
      r = []  # type: List[str]
      for s in l:
          # Strip spaces at end of line
          r.append(re.sub(r"\s+$", "", s))
  
      while len(r) > 0 and r[-1] == "":
          r.pop()
  
      return r
  
  
  def collapse_line_continuation(l: List[str]) -> List[str]:
      r = []  # type: List[str]
      cont = False
      for s in l:
          ss = re.sub(r"\\$", "", s)
          if cont:
              r[-1] += re.sub("^ +", "", ss)
          else:
              r.append(ss)
          cont = s.endswith("\\")
      return r
  
  
  def expand_variables(s: str) -> str:
      return s.replace("<ROOT>", root_dir)
  
  
  def expand_errors(input: List[str], output: List[str], fnam: str) -> None:
      """Transform comments such as '# E: message' or
      '# E:3: message' in input.
  
      The result is lines like 'fnam:line: error: message'.
      """
  
      for i in range(len(input)):
          # The first in the split things isn't a comment
          for possible_err_comment in input[i].split(" # ")[1:]:
              m = re.search(
                  r"^([ENW]):((?P<col>\d+):)? (?P<message>.*)$",
                  possible_err_comment.strip(),
              )
              if m:
                  if m.group(1) == "E":
                      severity = "error"
                  elif m.group(1) == "N":
                      severity = "note"
                  elif m.group(1) == "W":
                      severity = "warning"
                  col = m.group("col")
                  message = m.group("message")
                  message = message.replace("\\#", "#")  # adds back escaped # character
                  if col is None:
                      output.append(
                          "{}:{}: {}: {}".format(fnam, i + 1, severity, message)
                      )
                  else:
                      output.append(
                          "{}:{}:{}: {}: {}".format(fnam, i + 1, col, severity, message)
                      )
  
  
  def fix_win_path(line: str) -> str:
      r"""Changes Windows paths to Linux paths in error messages.
  
      E.g. foo\bar.py -> foo/bar.py.
      """
      line = line.replace(root_dir, root_dir.replace("\\", "/"))
      m = re.match(r"^([\S/]+):(\d+:)?(\s+.*)", line)
      if not m:
          return line
      else:
          filename, lineno, message = m.groups()
          return "{}:{}{}".format(filename.replace("\\", "/"), lineno or "", message)
  
  
  def fix_cobertura_filename(line: str) -> str:
      r"""Changes filename paths to Linux paths in Cobertura output files.
  
      E.g. filename="pkg\subpkg\a.py" -> filename="pkg/subpkg/a.py".
      """
      m = re.search(r'<class .* filename="(?P<filename>.*?)"', line)
      if not m:
          return line
      return "{}{}{}".format(
          line[: m.start(1)], m.group("filename").replace("\\", "/"), line[m.end(1) :]
      )
  
  
  ##
  #
  # pytest setup
  #
  ##
  
  
  # This function name is special to pytest.  See
  # https://docs.pytest.org/en/latest/reference.html#initialization-hooks
  def pytest_addoption(parser: Any) -> None:
      group = parser.getgroup("mypy")
      group.addoption(
          "--update-data",
          action="store_true",
          default=False,
          help="Update test data to reflect actual output"
          " (supported only for certain tests)",
      )
      group.addoption(
          "--save-failures-to",
          default=None,
          help="Copy the temp directories from failing tests to a target directory",
      )
      group.addoption(
          "--mypy-verbose",
          action="count",
          help="Set the verbose flag when creating mypy Options",
      )
      group.addoption(
          "--mypyc-showc",
          action="store_true",
          default=False,
          help="Display C code on mypyc test failures",
      )
  
  
  # This function name is special to pytest.  See
  # http://doc.pytest.org/en/latest/writing_plugins.html#collection-hooks
  def pytest_pycollect_makeitem(
      collector: Any, name: str, obj: object
  ) -> "Optional[Any]":
      """Called by pytest on each object in modules configured in conftest.py files.
  
      collector is pytest.Collector, returns Optional[pytest.Class]
      """
      if isinstance(obj, type):
          # Only classes derived from DataSuite contain test cases, not the DataSuite class itself
          if issubclass(obj, DataSuite) and obj is not DataSuite:
              # Non-None result means this obj is a test case.
              # The collect method of the returned DataSuiteCollector instance will be called later,
              # with self.obj being obj.
              return DataSuiteCollector(name, parent=collector)
      return None
  
  
  def split_test_cases(
      parent: "DataSuiteCollector", suite: "DataSuite", file: str
  ) -> Iterator["DataDrivenTestCase"]:
      """Iterate over raw test cases in file, at collection time, ignoring sub items.
  
      The collection phase is slow, so any heavy processing should be deferred to after
      uninteresting tests are filtered (when using -k PATTERN switch).
      """
      with open(file, encoding="utf-8") as f:
          data = f.read()
      cases = re.split(
          r"^\[case ([a-zA-Z_0-9]+)"
          r"(-writescache)?"
          r"(-only_when_cache|-only_when_nocache)?"
          r"(-posix|-windows)?"
          r"(-skip)?"
          r"\][ \t]*$\n",
          data,
          flags=re.DOTALL | re.MULTILINE,
      )
      line_no = cases[0].count("\n") + 1
      for i in range(1, len(cases), 6):
          name, writescache, only_when, platform_flag, skip, data = cases[i : i + 6]
          platform = platform_flag[1:] if platform_flag else None
          yield DataDrivenTestCase(
              parent,
              suite,
              file,
              name=add_test_name_suffix(name, suite.test_name_suffix),
              writescache=bool(writescache),
              only_when=only_when,
              platform=platform,
              skip=bool(skip),
              data=data,
              line=line_no,
          )
          line_no += data.count("\n") + 1
  
  
  class DataSuiteCollector(pytest.Class):  # type: ignore  # inheriting from Any
      def collect(self) -> Iterator[pytest.Item]:  # type: ignore
          """Called by pytest on each of the object returned from pytest_pycollect_makeitem"""
  
          # obj is the object for which pytest_pycollect_makeitem returned self.
          suite = self.obj  # type: DataSuite
          for f in suite.files:
              yield from split_test_cases(self, suite, os.path.join(suite.data_prefix, f))
  
  
  def add_test_name_suffix(name: str, suffix: str) -> str:
      # Find magic suffix of form "-foobar" (used for things like "-skip").
      m = re.search(r"-[-A-Za-z0-9]+$", name)
      if m:
          # Insert suite-specific test name suffix before the magic suffix
          # which must be the last thing in the test case name since we
          # are using endswith() checks.
          magic_suffix = m.group(0)
          return name[: -len(magic_suffix)] + suffix + magic_suffix
      else:
          return name + suffix
  
  
  def is_incremental(testcase: DataDrivenTestCase) -> bool:
      return "incremental" in testcase.name.lower() or "incremental" in testcase.file
  
  
  def has_stable_flags(testcase: DataDrivenTestCase) -> bool:
      if any(re.match(r"# flags[2-9]:", line) for line in testcase.input):
          return False
      for filename, contents in testcase.files:
          if os.path.basename(filename).startswith("mypy.ini."):
              return False
      return True
  
  
  class DataSuite:
      # option fields - class variables
      files = None  # type: List[str]
  
      base_path = test_temp_dir
  
      # Allow external users of the test code to override the data prefix
      data_prefix = test_data_prefix
  
      required_out_section = False
  
      native_sep = False
  
      # Name suffix automatically added to each test case in the suite (can be
      # used to distinguish test cases in suites that share data files)
      test_name_suffix = ""
  
      def setup(self) -> None:
          """Setup fixtures (ad-hoc)"""
          pass
  
      @abstractmethod
      def run_case(self, testcase: DataDrivenTestCase) -> None:
          raise NotImplementedError
  