text: """Tests for debugging machinery.
  """
  
  # Copyright (c) IPython Development Team.
  # Distributed under the terms of the Modified BSD License.
  
  import bdb
  import builtins
  import os
  import sys
  import platform
  
  from tempfile import NamedTemporaryFile
  from textwrap import dedent
  from unittest.mock import patch
  
  from IPython.core import debugger
  from IPython.testing import IPYTHON_TESTING_TIMEOUT_SCALE
  from IPython.testing.decorators import skip_win32
  import pytest
  
  #-----------------------------------------------------------------------------
  # Helper classes, from CPython's Pdb test suite
  #-----------------------------------------------------------------------------
  
  class _FakeInput(object):
      """
      A fake input stream for pdb's interactive debugger.  Whenever a
      line is read, print it (to simulate the user typing it), and then
      return it.  The set of lines to return is specified in the
      constructor; they should not have trailing newlines.
      """
      def __init__(self, lines):
          self.lines = iter(lines)
  
      def readline(self):
          line = next(self.lines)
          print(line)
          return line+'\n'
  
  class PdbTestInput(object):
      """Context manager that makes testing Pdb in doctests easier."""
  
      def __init__(self, input):
          self.input = input
  
      def __enter__(self):
          self.real_stdin = sys.stdin
          sys.stdin = _FakeInput(self.input)
  
      def __exit__(self, *exc):
          sys.stdin = self.real_stdin
  
  #-----------------------------------------------------------------------------
  # Tests
  #-----------------------------------------------------------------------------
  
  def test_ipdb_magics():
      '''Test calling some IPython magics from ipdb.
  
      First, set up some test functions and classes which we can inspect.
  
      >>> class ExampleClass(object):
      ...    """Docstring for ExampleClass."""
      ...    def __init__(self):
      ...        """Docstring for ExampleClass.__init__"""
      ...        pass
      ...    def __str__(self):
      ...        return "ExampleClass()"
  
      >>> def example_function(x, y, z="hello"):
      ...     """Docstring for example_function."""
      ...     pass
  
      >>> old_trace = sys.gettrace()
  
      Create a function which triggers ipdb.
  
      >>> def trigger_ipdb():
      ...    a = ExampleClass()
      ...    debugger.Pdb().set_trace()
  
      >>> with PdbTestInput([
      ...    'pdef example_function',
      ...    'pdoc ExampleClass',
      ...    'up',
      ...    'down',
      ...    'list',
      ...    'pinfo a',
      ...    'll',
      ...    'continue',
      ... ]):
      ...     trigger_ipdb()
      --Return--
      None
      > <doctest ...>(3)trigger_ipdb()
            1 def trigger_ipdb():
            2    a = ExampleClass()
      ----> 3    debugger.Pdb().set_trace()
      <BLANKLINE>
      ipdb> pdef example_function
       example_function(x, y, z='hello')
       ipdb> pdoc ExampleClass
      Class docstring:
          Docstring for ExampleClass.
      Init docstring:
          Docstring for ExampleClass.__init__
      ipdb> up
      > <doctest ...>(11)<module>()
            7    'pinfo a',
            8    'll',
            9    'continue',
           10 ]):
      ---> 11     trigger_ipdb()
      <BLANKLINE>
      ipdb> down
      None
      > <doctest ...>(3)trigger_ipdb()
            1 def trigger_ipdb():
            2    a = ExampleClass()
      ----> 3    debugger.Pdb().set_trace()
      <BLANKLINE>
      ipdb> list
            1 def trigger_ipdb():
            2    a = ExampleClass()
      ----> 3    debugger.Pdb().set_trace()
      <BLANKLINE>
      ipdb> pinfo a
      Type:           ExampleClass
      String form:    ExampleClass()
      Namespace:      Local...
      Docstring:      Docstring for ExampleClass.
      Init docstring: Docstring for ExampleClass.__init__
      ipdb> ll
            1 def trigger_ipdb():
            2    a = ExampleClass()
      ----> 3    debugger.Pdb().set_trace()
      <BLANKLINE>
      ipdb> continue
      
      Restore previous trace function, e.g. for coverage.py    
      
      >>> sys.settrace(old_trace)
      '''
  
  def test_ipdb_magics2():
      '''Test ipdb with a very short function.
      
      >>> old_trace = sys.gettrace()
  
      >>> def bar():
      ...     pass
  
      Run ipdb.
  
      >>> with PdbTestInput([
      ...    'continue',
      ... ]):
      ...     debugger.Pdb().runcall(bar)
      > <doctest ...>(2)bar()
            1 def bar():
      ----> 2    pass
      <BLANKLINE>
      ipdb> continue
      
      Restore previous trace function, e.g. for coverage.py    
      
      >>> sys.settrace(old_trace)
      '''
  
  def can_quit():
      '''Test that quit work in ipydb
  
      >>> old_trace = sys.gettrace()
  
      >>> def bar():
      ...     pass
  
      >>> with PdbTestInput([
      ...    'quit',
      ... ]):
      ...     debugger.Pdb().runcall(bar)
      > <doctest ...>(2)bar()
              1 def bar():
      ----> 2    pass
      <BLANKLINE>
      ipdb> quit
  
      Restore previous trace function, e.g. for coverage.py
  
      >>> sys.settrace(old_trace)
      '''
  
  
  def can_exit():
      '''Test that quit work in ipydb
  
      >>> old_trace = sys.gettrace()
  
      >>> def bar():
      ...     pass
  
      >>> with PdbTestInput([
      ...    'exit',
      ... ]):
      ...     debugger.Pdb().runcall(bar)
      > <doctest ...>(2)bar()
              1 def bar():
      ----> 2    pass
      <BLANKLINE>
      ipdb> exit
  
      Restore previous trace function, e.g. for coverage.py
  
      >>> sys.settrace(old_trace)
      '''
  
  
  def test_interruptible_core_debugger():
      """The debugger can be interrupted.
  
      The presumption is there is some mechanism that causes a KeyboardInterrupt
      (this is implemented in ipykernel).  We want to ensure the
      KeyboardInterrupt cause debugging to cease.
      """
      def raising_input(msg="", called=[0]):
          called[0] += 1
          assert called[0] == 1, "input() should only be called once!"
          raise KeyboardInterrupt()
  
      tracer_orig = sys.gettrace()
      try:
          with patch.object(builtins, "input", raising_input):
              debugger.InterruptiblePdb().set_trace()
              # The way this test will fail is by set_trace() never exiting,
              # resulting in a timeout by the test runner. The alternative
              # implementation would involve a subprocess, but that adds issues
              # with interrupting subprocesses that are rather complex, so it's
              # simpler just to do it this way.
      finally:
          # restore the original trace function
          sys.settrace(tracer_orig)
  
  
  @skip_win32
  def test_xmode_skip():
      """that xmode skip frames
  
      Not as a doctest as pytest does not run doctests.
      """
      import pexpect
      env = os.environ.copy()
      env["IPY_TEST_SIMPLE_PROMPT"] = "1"
  
      child = pexpect.spawn(
          sys.executable, ["-m", "IPython", "--colors=nocolor"], env=env
      )
      child.timeout = 15 * IPYTHON_TESTING_TIMEOUT_SCALE
  
      child.expect("IPython")
      child.expect("\n")
      child.expect_exact("In [1]")
  
      block = dedent(
          """
      def f():
          __tracebackhide__ = True
          g()
  
      def g():
          raise ValueError
  
      f()
      """
      )
  
      for line in block.splitlines():
          child.sendline(line)
          child.expect_exact(line)
      child.expect_exact("skipping")
  
      block = dedent(
          """
      def f():
          __tracebackhide__ = True
          g()
  
      def g():
          from IPython.core.debugger import set_trace
          set_trace()
  
      f()
      """
      )
  
      for line in block.splitlines():
          child.sendline(line)
          child.expect_exact(line)
  
      child.expect("ipdb>")
      child.sendline("w")
      child.expect("hidden")
      child.expect("ipdb>")
      child.sendline("skip_hidden false")
      child.sendline("w")
      child.expect("__traceba")
      child.expect("ipdb>")
  
      child.close()
  
  
  skip_decorators_blocks = (
      """
      def helpers_helper():
          pass # should not stop here except breakpoint
      """,
      """
      def helper_1():
          helpers_helper() # should not stop here
      """,
      """
      def helper_2():
          pass # should not stop here
      """,
      """
      def pdb_skipped_decorator2(function):
          def wrapped_fn(*args, **kwargs):
              __debuggerskip__ = True
              helper_2()
              __debuggerskip__ = False
              result = function(*args, **kwargs)
              __debuggerskip__ = True
              helper_2()
              return result
          return wrapped_fn
      """,
      """
      def pdb_skipped_decorator(function):
          def wrapped_fn(*args, **kwargs):
              __debuggerskip__ = True
              helper_1()
              __debuggerskip__ = False
              result = function(*args, **kwargs)
              __debuggerskip__ = True
              helper_2()
              return result
          return wrapped_fn
      """,
      """
      @pdb_skipped_decorator
      @pdb_skipped_decorator2
      def bar(x, y):
          return x * y
      """,
      """import IPython.terminal.debugger as ipdb""",
      """
      def f():
          ipdb.set_trace()
          bar(3, 4)
      """,
      """
      f()
      """,
  )
  
  
  def _decorator_skip_setup():
      import pexpect
  
      env = os.environ.copy()
      env["IPY_TEST_SIMPLE_PROMPT"] = "1"
  
      child = pexpect.spawn(
          sys.executable, ["-m", "IPython", "--colors=nocolor"], env=env
      )
      child.timeout = 15 * IPYTHON_TESTING_TIMEOUT_SCALE
  
      child.expect("IPython")
      child.expect("\n")
  
      child.timeout = 5 * IPYTHON_TESTING_TIMEOUT_SCALE
  
      dedented_blocks = [dedent(b).strip() for b in skip_decorators_blocks]
      in_prompt_number = 1
      for cblock in dedented_blocks:
          child.expect_exact(f"In [{in_prompt_number}]:")
          in_prompt_number += 1
          for line in cblock.splitlines():
              child.sendline(line)
              child.expect_exact(line)
          child.sendline("")
      return child
  
  
  @skip_win32
  def test_decorator_skip():
      """test that decorator frames can be skipped."""
  
      child = _decorator_skip_setup()
  
      child.expect_exact("3     bar(3, 4)")
      child.expect("ipdb>")
  
      child.expect("ipdb>")
      child.sendline("step")
      child.expect_exact("step")
  
      child.expect_exact("1 @pdb_skipped_decorator")
  
      child.sendline("s")
      child.expect_exact("return x * y")
  
      child.close()
  
  
  @pytest.mark.skipif(platform.python_implementation() == "PyPy", reason="issues on PyPy")
  @skip_win32
  def test_decorator_skip_disabled():
      """test that decorator frame skipping can be disabled"""
  
      child = _decorator_skip_setup()
  
      child.expect_exact("3     bar(3, 4)")
  
      for input_, expected in [
          ("skip_predicates debuggerskip False", ""),
          ("skip_predicates", "debuggerskip : False"),
          ("step", "---> 2     def wrapped_fn"),
          ("step", "----> 3         __debuggerskip__"),
          ("step", "----> 4         helper_1()"),
          ("step", "---> 1 def helper_1():"),
          ("next", "----> 2     helpers_helper()"),
          ("next", "--Return--"),
          ("next", "----> 5         __debuggerskip__ = False"),
      ]:
          child.expect("ipdb>")
          child.sendline(input_)
          child.expect_exact(input_)
          child.expect_exact(expected)
  
      child.close()
  
  
  @pytest.mark.skipif(platform.python_implementation() == "PyPy", reason="issues on PyPy")
  @skip_win32
  def test_decorator_skip_with_breakpoint():
      """test that decorator frame skipping can be disabled"""
  
      import pexpect
  
      env = os.environ.copy()
      env["IPY_TEST_SIMPLE_PROMPT"] = "1"
  
      child = pexpect.spawn(
          sys.executable, ["-m", "IPython", "--colors=nocolor"], env=env
      )
      child.timeout = 15 * IPYTHON_TESTING_TIMEOUT_SCALE
  
      child.expect("IPython")
      child.expect("\n")
  
      child.timeout = 5 * IPYTHON_TESTING_TIMEOUT_SCALE
  
      ### we need a filename, so we need to exec the full block with a filename
      with NamedTemporaryFile(suffix=".py", dir=".", delete=True) as tf:
  
          name = tf.name[:-3].split("/")[-1]
          tf.write("\n".join([dedent(x) for x in skip_decorators_blocks[:-1]]).encode())
          tf.flush()
          codeblock = f"from {name} import f"
  
          dedented_blocks = [
              codeblock,
              "f()",
          ]
  
          in_prompt_number = 1
          for cblock in dedented_blocks:
              child.expect_exact(f"In [{in_prompt_number}]:")
              in_prompt_number += 1
              for line in cblock.splitlines():
                  child.sendline(line)
                  child.expect_exact(line)
              child.sendline("")
  
          # as the filename does not exists, we'll rely on the filename prompt
          child.expect_exact("47     bar(3, 4)")
  
          for input_, expected in [
              (f"b {name}.py:3", ""),
              ("step", "1---> 3     pass # should not stop here except"),
              ("step", "---> 38 @pdb_skipped_decorator"),
              ("continue", ""),
          ]:
              child.expect("ipdb>")
              child.sendline(input_)
              child.expect_exact(input_)
              child.expect_exact(expected)
  
      child.close()
  
  
  @skip_win32
  def test_where_erase_value():
      """Test that `where` does not access f_locals and erase values."""
      import pexpect
  
      env = os.environ.copy()
      env["IPY_TEST_SIMPLE_PROMPT"] = "1"
  
      child = pexpect.spawn(
          sys.executable, ["-m", "IPython", "--colors=nocolor"], env=env
      )
      child.timeout = 15 * IPYTHON_TESTING_TIMEOUT_SCALE
  
      child.expect("IPython")
      child.expect("\n")
      child.expect_exact("In [1]")
  
      block = dedent(
          """
      def simple_f():
           myvar = 1
           print(myvar)
           1/0
           print(myvar)
      simple_f()    """
      )
  
      for line in block.splitlines():
          child.sendline(line)
          child.expect_exact(line)
      child.expect_exact("ZeroDivisionError")
      child.expect_exact("In [2]:")
  
      child.sendline("%debug")
  
      ##
      child.expect("ipdb>")
  
      child.sendline("myvar")
      child.expect("1")
  
      ##
      child.expect("ipdb>")
  
      child.sendline("myvar = 2")
  
      ##
      child.expect_exact("ipdb>")
  
      child.sendline("myvar")
  
      child.expect_exact("2")
  
      ##
      child.expect("ipdb>")
      child.sendline("where")
  
      ##
      child.expect("ipdb>")
      child.sendline("myvar")
  
      child.expect_exact("2")
      child.expect("ipdb>")
  
      child.close()
  