text: """Classes that replace tkinter gui objects used by an object being tested.
  
  A gui object is anything with a master or parent parameter, which is
  typically required in spite of what the doc strings say.
  """
  
  class Event:
      '''Minimal mock with attributes for testing event handlers.
  
      This is not a gui object, but is used as an argument for callbacks
      that access attributes of the event passed. If a callback ignores
      the event, other than the fact that is happened, pass 'event'.
  
      Keyboard, mouse, window, and other sources generate Event instances.
      Event instances have the following attributes: serial (number of
      event), time (of event), type (of event as number), widget (in which
      event occurred), and x,y (position of mouse). There are other
      attributes for specific events, such as keycode for key events.
      tkinter.Event.__doc__ has more but is still not complete.
      '''
      def __init__(self, **kwds):
          "Create event with attributes needed for test"
          self.__dict__.update(kwds)
  
  class Var:
      "Use for String/Int/BooleanVar: incomplete"
      def __init__(self, master=None, value=None, name=None):
          self.master = master
          self.value = value
          self.name = name
      def set(self, value):
          self.value = value
      def get(self):
          return self.value
  
  class Mbox_func:
      """Generic mock for messagebox functions, which all have the same signature.
  
      Instead of displaying a message box, the mock's call method saves the
      arguments as instance attributes, which test functions can then examine.
      The test can set the result returned to ask function
      """
      def __init__(self, result=None):
          self.result = result  # Return None for all show funcs
      def __call__(self, title, message, *args, **kwds):
          # Save all args for possible examination by tester
          self.title = title
          self.message = message
          self.args = args
          self.kwds = kwds
          return self.result  # Set by tester for ask functions
  
  class Mbox:
      """Mock for tkinter.messagebox with an Mbox_func for each function.
  
      This module was 'tkMessageBox' in 2.x; hence the 'import as' in  3.x.
      Example usage in test_module.py for testing functions in module.py:
      ---
  from idlelib.idle_test.mock_tk import Mbox
  import module
  
  orig_mbox = module.tkMessageBox
  showerror = Mbox.showerror  # example, for attribute access in test methods
  
  class Test(unittest.TestCase):
  
      @classmethod
      def setUpClass(cls):
          module.tkMessageBox = Mbox
  
      @classmethod
      def tearDownClass(cls):
          module.tkMessageBox = orig_mbox
      ---
      For 'ask' functions, set func.result return value before calling the method
      that uses the message function. When tkMessageBox functions are the
      only gui alls in a method, this replacement makes the method gui-free,
      """
      askokcancel = Mbox_func()     # True or False
      askquestion = Mbox_func()     # 'yes' or 'no'
      askretrycancel = Mbox_func()  # True or False
      askyesno = Mbox_func()        # True or False
      askyesnocancel = Mbox_func()  # True, False, or None
      showerror = Mbox_func()    # None
      showinfo = Mbox_func()     # None
      showwarning = Mbox_func()  # None
  
  from _tkinter import TclError
  
  class Text:
      """A semi-functional non-gui replacement for tkinter.Text text editors.
  
      The mock's data model is that a text is a list of \n-terminated lines.
      The mock adds an empty string at  the beginning of the list so that the
      index of actual lines start at 1, as with Tk. The methods never see this.
      Tk initializes files with a terminal \n that cannot be deleted. It is
      invisible in the sense that one cannot move the cursor beyond it.
  
      This class is only tested (and valid) with strings of ascii chars.
      For testing, we are not concerned with Tk Text's treatment of,
      for instance, 0-width characters or character + accent.
     """
      def __init__(self, master=None, cnf={}, **kw):
          '''Initialize mock, non-gui, text-only Text widget.
  
          At present, all args are ignored. Almost all affect visual behavior.
          There are just a few Text-only options that affect text behavior.
          '''
          self.data = ['', '\n']
  
      def index(self, index):
          "Return string version of index decoded according to current text."
          return "%s.%s" % self._decode(index, endflag=1)
  
      def _decode(self, index, endflag=0):
          """Return a (line, char) tuple of int indexes into self.data.
  
          This implements .index without converting the result back to a string.
          The result is constrained by the number of lines and linelengths of
          self.data. For many indexes, the result is initially (1, 0).
  
          The input index may have any of several possible forms:
          * line.char float: converted to 'line.char' string;
          * 'line.char' string, where line and char are decimal integers;
          * 'line.char lineend', where lineend='lineend' (and char is ignored);
          * 'line.end', where end='end' (same as above);
          * 'insert', the positions before terminal \n;
          * 'end', whose meaning depends on the endflag passed to ._endex.
          * 'sel.first' or 'sel.last', where sel is a tag -- not implemented.
          """
          if isinstance(index, (float, bytes)):
              index = str(index)
          try:
              index=index.lower()
          except AttributeError:
              raise TclError('bad text index "%s"' % index) from None
  
          lastline =  len(self.data) - 1  # same as number of text lines
          if index == 'insert':
              return lastline, len(self.data[lastline]) - 1
          elif index == 'end':
              return self._endex(endflag)
  
          line, char = index.split('.')
          line = int(line)
  
          # Out of bounds line becomes first or last ('end') index
          if line < 1:
              return 1, 0
          elif line > lastline:
              return self._endex(endflag)
  
          linelength = len(self.data[line])  -1  # position before/at \n
          if char.endswith(' lineend') or char == 'end':
              return line, linelength
              # Tk requires that ignored chars before ' lineend' be valid int
  
          # Out of bounds char becomes first or last index of line
          char = int(char)
          if char < 0:
              char = 0
          elif char > linelength:
              char = linelength
          return line, char
  
      def _endex(self, endflag):
          '''Return position for 'end' or line overflow corresponding to endflag.
  
         -1: position before terminal \n; for .insert(), .delete
         0: position after terminal \n; for .get, .delete index 1
         1: same viewed as beginning of non-existent next line (for .index)
         '''
          n = len(self.data)
          if endflag == 1:
              return n, 0
          else:
              n -= 1
              return n, len(self.data[n]) + endflag
  
  
      def insert(self, index, chars):
          "Insert chars before the character at index."
  
          if not chars:  # ''.splitlines() is [], not ['']
              return
          chars = chars.splitlines(True)
          if chars[-1][-1] == '\n':
              chars.append('')
          line, char = self._decode(index, -1)
          before = self.data[line][:char]
          after = self.data[line][char:]
          self.data[line] = before + chars[0]
          self.data[line+1:line+1] = chars[1:]
          self.data[line+len(chars)-1] += after
  
  
      def get(self, index1, index2=None):
          "Return slice from index1 to index2 (default is 'index1+1')."
  
          startline, startchar = self._decode(index1)
          if index2 is None:
              endline, endchar = startline, startchar+1
          else:
              endline, endchar = self._decode(index2)
  
          if startline == endline:
              return self.data[startline][startchar:endchar]
          else:
              lines = [self.data[startline][startchar:]]
              for i in range(startline+1, endline):
                  lines.append(self.data[i])
              lines.append(self.data[endline][:endchar])
              return ''.join(lines)
  
  
      def delete(self, index1, index2=None):
          '''Delete slice from index1 to index2 (default is 'index1+1').
  
          Adjust default index2 ('index+1) for line ends.
          Do not delete the terminal \n at the very end of self.data ([-1][-1]).
          '''
          startline, startchar = self._decode(index1, -1)
          if index2 is None:
              if startchar < len(self.data[startline])-1:
                  # not deleting \n
                  endline, endchar = startline, startchar+1
              elif startline < len(self.data) - 1:
                  # deleting non-terminal \n, convert 'index1+1 to start of next line
                  endline, endchar = startline+1, 0
              else:
                  # do not delete terminal \n if index1 == 'insert'
                  return
          else:
              endline, endchar = self._decode(index2, -1)
              # restricting end position to insert position excludes terminal \n
  
          if startline == endline and startchar < endchar:
              self.data[startline] = self.data[startline][:startchar] + \
                                               self.data[startline][endchar:]
          elif startline < endline:
              self.data[startline] = self.data[startline][:startchar] + \
                                     self.data[endline][endchar:]
              startline += 1
              for i in range(startline, endline+1):
                  del self.data[startline]
  
      def compare(self, index1, op, index2):
          line1, char1 = self._decode(index1)
          line2, char2 = self._decode(index2)
          if op == '<':
              return line1 < line2 or line1 == line2 and char1 < char2
          elif op == '<=':
              return line1 < line2 or line1 == line2 and char1 <= char2
          elif op == '>':
              return line1 > line2 or line1 == line2 and char1 > char2
          elif op == '>=':
              return line1 > line2 or line1 == line2 and char1 >= char2
          elif op == '==':
              return line1 == line2 and char1 == char2
          elif op == '!=':
              return line1 != line2 or  char1 != char2
          else:
              raise TclError('''bad comparison operator "%s": '''
                                    '''must be <, <=, ==, >=, >, or !=''' % op)
  
      # The following Text methods normally do something and return None.
      # Whether doing nothing is sufficient for a test will depend on the test.
  
      def mark_set(self, name, index):
          "Set mark *name* before the character at index."
          pass
  
      def mark_unset(self, *markNames):
          "Delete all marks in markNames."
  
      def tag_remove(self, tagName, index1, index2=None):
          "Remove tag tagName from all characters between index1 and index2."
          pass
  
      # The following Text methods affect the graphics screen and return None.
      # Doing nothing should always be sufficient for tests.
  
      def scan_dragto(self, x, y):
          "Adjust the view of the text according to scan_mark"
  
      def scan_mark(self, x, y):
          "Remember the current X, Y coordinates."
  
      def see(self, index):
          "Scroll screen to make the character at INDEX is visible."
          pass
  
      #  The following is a Misc method inherited by Text.
      # It should properly go in a Misc mock, but is included here for now.
  
      def bind(sequence=None, func=None, add=None):
          "Bind to this widget at event sequence a call to function func."
          pass
  
  class Entry:
      "Mock for tkinter.Entry."
      def focus_set(self):
          pass
  